[PATCH 0/2] media: iris: add vbv delay support

[PATCH 0/2] media: iris: add vbv delay support

[Sachin Kumar Garg]

This series adds VBV_DELAY (V4L2_CID_MPEG_VIDEO_VBV_DELAY) support
for Qualcomm iris encoder sessions, allowing users to configure the
initial VBV (Video Buffer Verifier) delay for CBR-encoded streams.
This is useful for latency-sensitive encoding use cases (e.g.
low-latency streaming) where the client needs explicit control over
the encoder's buffering delay.

Patch 1 is a prerequisite for patch 2. The PIPE capability (control
over the number of VPP hardware pipes used for a session) was
previously only wired up for decoder sessions. Achieving low VBV delay
values (34-100 ms) requires the encoder to be constrained to a single
VPP pipe, so patch 1 enables the PIPE capability on the encoder path as
well, which patch 2 then relies on to force single-pipe operation when
VBV delay falls in that low-latency range.

Patch 2 adds the VBV_DELAY capability: it registers HFI_PROP_VBV_DELAY,
wires up the V4L2_CID_MPEG_VIDEO_VBV_DELAY control for the gen2
encoder, and only applies the property when rate control is set to CBR
since VBV delay is only meaningful for constant-bitrate encoding.
It adds vbv_delay support for iris HFI Gen2 based targets (qcs8300,
sm8550, sm8650, sm8750, x1p42100). Support for HFI Gen1 targets will
be added in a follow-up series.

This series has been verified with GST level testing.
Command used:
gst-launch-1.0 -v videotestsrc ! video/x-raw,format=NV12, \
width=1280,height=720,framerate=30/1 ! v4l2h264enc output-io-mode=4 \
capture-io-mode=4 extra-controls="controls,video_bitrate_mode=1, \
initial_delay_for_vbv_control=300;" ! filesink location=/opt/test_enc.h264

Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
---
Sachin Kumar Garg (2):
      media: iris: enable pipe for hfi gen2 encoder
      media: iris: add support for vbv delay

 drivers/media/platform/qcom/iris/iris_ctrls.c      | 47 ++++++++++++++++++++--
 drivers/media/platform/qcom/iris/iris_ctrls.h      |  1 +
 drivers/media/platform/qcom/iris/iris_hfi_gen2.c   | 19 ++++++++-
 .../platform/qcom/iris/iris_hfi_gen2_defines.h     |  1 +
 .../platform/qcom/iris/iris_platform_common.h      |  1 +
 5 files changed, 65 insertions(+), 4 deletions(-)
---
base-commit: a52e6f7923c17a672135b485ffd96fbd72f46267
change-id: 20260730-iris_vbv_delay-343d2fa30842

Best regards,
-- 
Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>

[PATCH 1/2] media: iris: enable pipe for hfi gen2 encoder

[Sachin Kumar Garg]

Currently the PIPE capability (HFI_PROP_PIPE / work-route) is only
wired up for the HFI Gen2 decoder. Add a PIPE entry to the HFI Gen2
encoder instance capability table, and extend the encoder
branch of iris_session_init_caps() to derive PIPE's min/max/value
from the platform's num_vpp_pipe, mirroring the existing decoder
handling.

Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
---
 drivers/media/platform/qcom/iris/iris_ctrls.c    | 16 +++++++++++++---
 drivers/media/platform/qcom/iris/iris_hfi_gen2.c |  7 +++++++
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.c b/drivers/media/platform/qcom/iris/iris_ctrls.c
index 10e33b8a73f6..33114d80aa68 100644
--- a/drivers/media/platform/qcom/iris/iris_ctrls.c
+++ b/drivers/media/platform/qcom/iris/iris_ctrls.c
@@ -453,13 +453,23 @@ void iris_session_init_caps(struct iris_core *core)
 			continue;
 
 		core->inst_fw_caps_enc[cap_id].cap_id = caps[i].cap_id;
-		core->inst_fw_caps_enc[cap_id].min = caps[i].min;
-		core->inst_fw_caps_enc[cap_id].max = caps[i].max;
 		core->inst_fw_caps_enc[cap_id].step_or_mask = caps[i].step_or_mask;
-		core->inst_fw_caps_enc[cap_id].value = caps[i].value;
 		core->inst_fw_caps_enc[cap_id].flags = caps[i].flags;
 		core->inst_fw_caps_enc[cap_id].hfi_id = caps[i].hfi_id;
 		core->inst_fw_caps_enc[cap_id].set = caps[i].set;
+
+		if (cap_id == PIPE) {
+			core->inst_fw_caps_enc[cap_id].value =
+				core->iris_platform_data->num_vpp_pipe;
+			core->inst_fw_caps_enc[cap_id].min =
+				core->iris_platform_data->num_vpp_pipe;
+			core->inst_fw_caps_enc[cap_id].max =
+				core->iris_platform_data->num_vpp_pipe;
+		} else {
+			core->inst_fw_caps_enc[cap_id].min = caps[i].min;
+			core->inst_fw_caps_enc[cap_id].max = caps[i].max;
+			core->inst_fw_caps_enc[cap_id].value = caps[i].value;
+		}
 	}
 }
 
diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
index acc0ed8adda1..45a418fde7e9 100644
--- a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
+++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
@@ -365,6 +365,13 @@ static const struct platform_inst_fw_cap inst_fw_cap_sm8550_enc[] = {
 		.hfi_id = HFI_PROP_STAGE,
 		.set = iris_set_stage,
 	},
+	{
+		.cap_id = PIPE,
+		/* .max, .min and .value are set via platform data */
+		.step_or_mask = 1,
+		.hfi_id = HFI_PROP_PIPE,
+		.set = iris_set_pipe,
+	},
 	{
 		.cap_id = HEADER_MODE,
 		.min = V4L2_MPEG_VIDEO_HEADER_MODE_SEPARATE,

-- 
2.34.1

Re: [PATCH 1/2] media: iris: enable pipe for hfi gen2 encoder

[Vikash Garodia]

On 7/30/2026 8:25 PM, Sachin Kumar Garg wrote:
> Currently the PIPE capability (HFI_PROP_PIPE / work-route) is only
> wired up for the HFI Gen2 decoder. Add a PIPE entry to the HFI Gen2
> encoder instance capability table, and extend the encoder
> branch of iris_session_init_caps() to derive PIPE's min/max/value
> from the platform's num_vpp_pipe, mirroring the existing decoder
> handling.
> 
> Signed-off-by: Sachin Kumar Garg<sachin.garg@oss.qualcomm.com>
> ---
>   drivers/media/platform/qcom/iris/iris_ctrls.c    | 16 +++++++++++++---
>   drivers/media/platform/qcom/iris/iris_hfi_gen2.c |  7 +++++++
>   2 files changed, 20 insertions(+), 3 deletions(-)

Reviewed-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>

[PATCH 2/2] media: iris: add support for vbv delay

[Sachin Kumar Garg]

Add the VBV_DELAY instance capability for the HFI Gen2 encoder,
exposed to userspace via V4L2_CID_MPEG_VIDEO_VBV_DELAY and mapped to
HFI_PROP_VBV_DELAY through a new iris_set_vbv_delay(). The property
is only meaningful for CBR rate-control modes.

Low VBV delay values (34-100 ms) require the encoder to run
with a single video pipe, so extend iris_set_pipe() to force
work_route to 1 whenever the configured VBV_DELAY falls in that
range.

Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
---
 drivers/media/platform/qcom/iris/iris_ctrls.c      | 31 ++++++++++++++++++++++
 drivers/media/platform/qcom/iris/iris_ctrls.h      |  1 +
 drivers/media/platform/qcom/iris/iris_hfi_gen2.c   | 12 ++++++++-
 .../platform/qcom/iris/iris_hfi_gen2_defines.h     |  1 +
 .../platform/qcom/iris/iris_platform_common.h      |  1 +
 5 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.c b/drivers/media/platform/qcom/iris/iris_ctrls.c
index 33114d80aa68..0ad873f3be78 100644
--- a/drivers/media/platform/qcom/iris/iris_ctrls.c
+++ b/drivers/media/platform/qcom/iris/iris_ctrls.c
@@ -154,6 +154,8 @@ static enum platform_inst_fw_cap_type iris_get_cap_id(u32 id)
 		return LAYER4_BITRATE_HEVC;
 	case V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L5_BR:
 		return LAYER5_BITRATE_HEVC;
+	case V4L2_CID_MPEG_VIDEO_VBV_DELAY:
+		return VBV_DELAY;
 	default:
 		return INST_FW_CAP_MAX;
 	}
@@ -297,6 +299,8 @@ static u32 iris_get_v4l2_id(enum platform_inst_fw_cap_type cap_id)
 		return V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L4_BR;
 	case LAYER5_BITRATE_HEVC:
 		return V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L5_BR;
+	case VBV_DELAY:
+		return V4L2_CID_MPEG_VIDEO_VBV_DELAY;
 	default:
 		return 0;
 	}
@@ -544,6 +548,11 @@ int iris_set_pipe(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id)
 	u32 work_route = inst->fw_caps[PIPE].value;
 	u32 hfi_id = inst->fw_caps[cap_id].hfi_id;
 
+	if (inst->domain == ENCODER) {
+		if (inst->fw_caps[VBV_DELAY].value > 34 && inst->fw_caps[VBV_DELAY].value < 100)
+			work_route = 1;
+	}
+
 	return hfi_ops->session_set_property(inst, hfi_id,
 					     HFI_HOST_FLAGS_NONE,
 					     iris_get_port_info(inst, cap_id),
@@ -1487,6 +1496,28 @@ int iris_set_layer_bitrate(struct iris_inst *inst, enum platform_inst_fw_cap_typ
 					     &bitrate, sizeof(u32));
 }
 
+int iris_set_vbv_delay(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id)
+{
+	const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops;
+	u32 hfi_id = inst->fw_caps[cap_id].hfi_id;
+	u32 rc_type = inst->hfi_rc_type;
+	u32 hfi_val;
+
+	if (rc_type != HFI_RC_CBR_VFR &&
+	    rc_type != HFI_RC_CBR_CFR) {
+		dev_err(inst->core->dev, "vbv_delay unsupported, rc_type: %#x\n", rc_type);
+		return -EINVAL;
+	}
+
+	hfi_val = inst->fw_caps[cap_id].value;
+
+	return hfi_ops->session_set_property(inst, hfi_id,
+					     HFI_HOST_FLAGS_NONE,
+					     iris_get_port_info(inst, cap_id),
+					     HFI_PAYLOAD_U32,
+					     &hfi_val, sizeof(u32));
+}
+
 int iris_set_properties(struct iris_inst *inst, u32 plane)
 {
 	const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops;
diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.h b/drivers/media/platform/qcom/iris/iris_ctrls.h
index 3c462ec9190b..16939e31c784 100644
--- a/drivers/media/platform/qcom/iris/iris_ctrls.h
+++ b/drivers/media/platform/qcom/iris/iris_ctrls.h
@@ -47,6 +47,7 @@ int iris_set_layer_type(struct iris_inst *inst, enum platform_inst_fw_cap_type c
 int iris_set_layer_count_gen1(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id);
 int iris_set_layer_count_gen2(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id);
 int iris_set_layer_bitrate(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id);
+int iris_set_vbv_delay(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id);
 int iris_set_properties(struct iris_inst *inst, u32 plane);
 
 #endif
diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
index 45a418fde7e9..716947f256f1 100644
--- a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
+++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
@@ -944,7 +944,17 @@ static const struct platform_inst_fw_cap inst_fw_cap_sm8550_enc[] = {
 		.flags = CAP_FLAG_OUTPUT_PORT | CAP_FLAG_INPUT_PORT |
 			CAP_FLAG_DYNAMIC_ALLOWED,
 		.set = iris_set_layer_bitrate,
-	}
+	},
+	{
+		.cap_id = VBV_DELAY,
+		.min = 34,
+		.max = 300,
+		.step_or_mask = 1,
+		.value = 300,
+		.hfi_id = HFI_PROP_VBV_DELAY,
+		.flags = CAP_FLAG_OUTPUT_PORT,
+		.set = iris_set_vbv_delay,
+	},
 };
 
 static const u32 sm8550_vdec_input_config_params_default[] = {
diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h b/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h
index 776b21cd11b2..19d04981cdb9 100644
--- a/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h
+++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h
@@ -127,6 +127,7 @@ enum hfi_flip {
 #define HFI_PROP_BUFFER_MARK			0x0300016c
 #define HFI_PROP_WORST_COMPRESSION_RATIO	0x03000174
 #define HFI_PROP_WORST_COMPLEXITY_FACTOR	0x03000175
+#define HFI_PROP_VBV_DELAY			0x03000176
 #define HFI_PROP_RAW_RESOLUTION		0x03000178
 #define HFI_PROP_TOTAL_PEAK_BITRATE		0x0300017C
 #define HFI_PROP_AV1_FILM_GRAIN_PRESENT	0x03000180
diff --git a/drivers/media/platform/qcom/iris/iris_platform_common.h b/drivers/media/platform/qcom/iris/iris_platform_common.h
index c9256f2323dc..a533740ced7c 100644
--- a/drivers/media/platform/qcom/iris/iris_platform_common.h
+++ b/drivers/media/platform/qcom/iris/iris_platform_common.h
@@ -183,6 +183,7 @@ enum platform_inst_fw_cap_type {
 	LAYER3_BITRATE_HEVC,
 	LAYER4_BITRATE_HEVC,
 	LAYER5_BITRATE_HEVC,
+	VBV_DELAY,
 	INST_FW_CAP_MAX,
 };
 

-- 
2.34.1

Re: [PATCH 2/2] media: iris: add support for vbv delay

[Vikash Garodia]

On 7/30/2026 8:25 PM, Sachin Kumar Garg wrote:
> Add the VBV_DELAY instance capability for the HFI Gen2 encoder,
> exposed to userspace via V4L2_CID_MPEG_VIDEO_VBV_DELAY and mapped to
> HFI_PROP_VBV_DELAY through a new iris_set_vbv_delay(). The property
> is only meaningful for CBR rate-control modes.
> 
> Low VBV delay values (34-100 ms) require the encoder to run
> with a single video pipe, so extend iris_set_pipe() to force
> work_route to 1 whenever the configured VBV_DELAY falls in that
> range.
> 
> Signed-off-by: Sachin Kumar Garg<sachin.garg@oss.qualcomm.com>
> ---
>   drivers/media/platform/qcom/iris/iris_ctrls.c      | 31 ++++++++++++++++++++++
>   drivers/media/platform/qcom/iris/iris_ctrls.h      |  1 +
>   drivers/media/platform/qcom/iris/iris_hfi_gen2.c   | 12 ++++++++-
>   .../platform/qcom/iris/iris_hfi_gen2_defines.h     |  1 +
>   .../platform/qcom/iris/iris_platform_common.h      |  1 +
>   5 files changed, 45 insertions(+), 1 deletion(-)

Reviewed-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>

[PATCH v2 0/2] media: iris: add vbv delay support

[Sachin Kumar Garg]

This series adds VBV_DELAY (V4L2_CID_MPEG_VIDEO_VBV_DELAY) support
for Qualcomm iris encoder sessions, allowing users to configure the
initial VBV (Video Buffer Verifier) delay for CBR-encoded streams.
This is useful for latency-sensitive encoding use cases (e.g.
low-latency streaming) where the client needs explicit control over
the encoder's buffering delay.

Patch 1 is a prerequisite for patch 2. The PIPE capability (control
over the number of VPP hardware pipes used for a session) was
previously only wired up for decoder sessions. Achieving low VBV delay
values (34-100 ms) requires the encoder to be constrained to a single
VPP pipe, so patch 1 enables the PIPE capability on the encoder path as
well, which patch 2 then relies on to force single-pipe operation when
VBV delay falls in that low-latency range.

Patch 2 adds the VBV_DELAY capability: it registers HFI_PROP_VBV_DELAY,
wires up the V4L2_CID_MPEG_VIDEO_VBV_DELAY control for the gen2
encoder, and only applies the property when rate control is set to CBR
since VBV delay is only meaningful for constant-bitrate encoding.
It adds vbv_delay support for iris HFI Gen2 based targets (qcs8300,
sm8550, sm8650, sm8750, x1p42100). Support for HFI Gen1 targets will
be added in a follow-up series.

This series has been verified with GST level testing.
Command used:
gst-launch-1.0 -v videotestsrc ! video/x-raw,format=NV12, \
width=1280,height=720,framerate=30/1 ! v4l2h264enc output-io-mode=4 \
capture-io-mode=4 extra-controls="controls,video_bitrate_mode=1, \
initial_delay_for_vbv_control=300;" ! filesink location=/opt/test_enc.h264

Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
---
Changes in v2:
- iris_set_pipe(): use inclusive VBV_DELAY bounds (>= 34 && <= 100 ms)
  matching the documented range.
- iris_set_pipe(): only force single-pipe under CBR rate control so
  a stale in-range VBV_DELAY no longer affects non-CBR streams.
- iris_set_pipe(): read fw_caps[VBV_DELAY].value once instead of
  twice in the same condition, and derive the default work_route from
  the immutable fw_caps[PIPE].max instead of the self-mutated .value,
  writing the final decision back into .value so frequency scaling
  picks up the corrected pipe count instead of a stale one.
- iris_set_vbv_delay(): drop the dev_err() logged for non-CBR rate
  control; that is an expected, valid configuration, not an error.
- Link to v1: https://lore.kernel.org/r/20260730-iris_vbv_delay-v1-0-7b5a7953bcdf@oss.qualcomm.com

---
Sachin Kumar Garg (2):
      media: iris: enable pipe for hfi gen2 encoder
      media: iris: add support for vbv delay

 drivers/media/platform/qcom/iris/iris_ctrls.c      | 52 ++++++++++++++++++++--
 drivers/media/platform/qcom/iris/iris_ctrls.h      |  1 +
 drivers/media/platform/qcom/iris/iris_hfi_gen2.c   | 19 +++++++-
 .../platform/qcom/iris/iris_hfi_gen2_defines.h     |  1 +
 .../platform/qcom/iris/iris_platform_common.h      |  1 +
 5 files changed, 69 insertions(+), 5 deletions(-)
---
base-commit: a52e6f7923c17a672135b485ffd96fbd72f46267
change-id: 20260730-iris_vbv_delay-343d2fa30842

Best regards,
-- 
Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>

[PATCH v2 1/2] media: iris: enable pipe for hfi gen2 encoder

[Sachin Kumar Garg]

Currently the PIPE capability (HFI_PROP_PIPE / work-route) is only
wired up for the HFI Gen2 decoder. Add a PIPE entry to the HFI Gen2
encoder instance capability table, and extend the encoder
branch of iris_session_init_caps() to derive PIPE's min/max/value
from the platform's num_vpp_pipe, mirroring the existing decoder
handling.

Reviewed-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
---
 drivers/media/platform/qcom/iris/iris_ctrls.c    | 16 +++++++++++++---
 drivers/media/platform/qcom/iris/iris_hfi_gen2.c |  7 +++++++
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.c b/drivers/media/platform/qcom/iris/iris_ctrls.c
index 10e33b8a73f6..33114d80aa68 100644
--- a/drivers/media/platform/qcom/iris/iris_ctrls.c
+++ b/drivers/media/platform/qcom/iris/iris_ctrls.c
@@ -453,13 +453,23 @@ void iris_session_init_caps(struct iris_core *core)
 			continue;
 
 		core->inst_fw_caps_enc[cap_id].cap_id = caps[i].cap_id;
-		core->inst_fw_caps_enc[cap_id].min = caps[i].min;
-		core->inst_fw_caps_enc[cap_id].max = caps[i].max;
 		core->inst_fw_caps_enc[cap_id].step_or_mask = caps[i].step_or_mask;
-		core->inst_fw_caps_enc[cap_id].value = caps[i].value;
 		core->inst_fw_caps_enc[cap_id].flags = caps[i].flags;
 		core->inst_fw_caps_enc[cap_id].hfi_id = caps[i].hfi_id;
 		core->inst_fw_caps_enc[cap_id].set = caps[i].set;
+
+		if (cap_id == PIPE) {
+			core->inst_fw_caps_enc[cap_id].value =
+				core->iris_platform_data->num_vpp_pipe;
+			core->inst_fw_caps_enc[cap_id].min =
+				core->iris_platform_data->num_vpp_pipe;
+			core->inst_fw_caps_enc[cap_id].max =
+				core->iris_platform_data->num_vpp_pipe;
+		} else {
+			core->inst_fw_caps_enc[cap_id].min = caps[i].min;
+			core->inst_fw_caps_enc[cap_id].max = caps[i].max;
+			core->inst_fw_caps_enc[cap_id].value = caps[i].value;
+		}
 	}
 }
 
diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
index acc0ed8adda1..45a418fde7e9 100644
--- a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
+++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
@@ -365,6 +365,13 @@ static const struct platform_inst_fw_cap inst_fw_cap_sm8550_enc[] = {
 		.hfi_id = HFI_PROP_STAGE,
 		.set = iris_set_stage,
 	},
+	{
+		.cap_id = PIPE,
+		/* .max, .min and .value are set via platform data */
+		.step_or_mask = 1,
+		.hfi_id = HFI_PROP_PIPE,
+		.set = iris_set_pipe,
+	},
 	{
 		.cap_id = HEADER_MODE,
 		.min = V4L2_MPEG_VIDEO_HEADER_MODE_SEPARATE,

-- 
2.34.1

[PATCH v2 2/2] media: iris: add support for vbv delay

[Sachin Kumar Garg]

Add the VBV_DELAY instance capability for the HFI Gen2 encoder,
exposed to userspace via V4L2_CID_MPEG_VIDEO_VBV_DELAY and mapped to
HFI_PROP_VBV_DELAY through a new iris_set_vbv_delay(). The property
is only meaningful for CBR rate-control modes.

Low VBV delay values (34-100 ms) require the encoder to run
with a single video pipe, so extend iris_set_pipe() to force
work_route to 1 whenever the configured VBV_DELAY falls in that
range.

Reviewed-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
---
 drivers/media/platform/qcom/iris/iris_ctrls.c      | 36 +++++++++++++++++++++-
 drivers/media/platform/qcom/iris/iris_ctrls.h      |  1 +
 drivers/media/platform/qcom/iris/iris_hfi_gen2.c   | 12 +++++++-
 .../platform/qcom/iris/iris_hfi_gen2_defines.h     |  1 +
 .../platform/qcom/iris/iris_platform_common.h      |  1 +
 5 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.c b/drivers/media/platform/qcom/iris/iris_ctrls.c
index 33114d80aa68..53d8b1ba15fe 100644
--- a/drivers/media/platform/qcom/iris/iris_ctrls.c
+++ b/drivers/media/platform/qcom/iris/iris_ctrls.c
@@ -154,6 +154,8 @@ static enum platform_inst_fw_cap_type iris_get_cap_id(u32 id)
 		return LAYER4_BITRATE_HEVC;
 	case V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L5_BR:
 		return LAYER5_BITRATE_HEVC;
+	case V4L2_CID_MPEG_VIDEO_VBV_DELAY:
+		return VBV_DELAY;
 	default:
 		return INST_FW_CAP_MAX;
 	}
@@ -297,6 +299,8 @@ static u32 iris_get_v4l2_id(enum platform_inst_fw_cap_type cap_id)
 		return V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L4_BR;
 	case LAYER5_BITRATE_HEVC:
 		return V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L5_BR;
+	case VBV_DELAY:
+		return V4L2_CID_MPEG_VIDEO_VBV_DELAY;
 	default:
 		return 0;
 	}
@@ -541,8 +545,18 @@ int iris_set_stage(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id
 int iris_set_pipe(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id)
 {
 	const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops;
-	u32 work_route = inst->fw_caps[PIPE].value;
+	u32 work_route = inst->fw_caps[PIPE].max;
 	u32 hfi_id = inst->fw_caps[cap_id].hfi_id;
+	u32 vbv_delay;
+
+	if (inst->domain == ENCODER &&
+	    (inst->hfi_rc_type == HFI_RC_CBR_VFR || inst->hfi_rc_type == HFI_RC_CBR_CFR)) {
+		vbv_delay = inst->fw_caps[VBV_DELAY].value;
+		if (vbv_delay >= 34 && vbv_delay <= 100)
+			work_route = 1;
+	}
+
+	inst->fw_caps[PIPE].value = work_route;
 
 	return hfi_ops->session_set_property(inst, hfi_id,
 					     HFI_HOST_FLAGS_NONE,
@@ -1487,6 +1501,26 @@ int iris_set_layer_bitrate(struct iris_inst *inst, enum platform_inst_fw_cap_typ
 					     &bitrate, sizeof(u32));
 }
 
+int iris_set_vbv_delay(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id)
+{
+	const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops;
+	u32 hfi_id = inst->fw_caps[cap_id].hfi_id;
+	u32 rc_type = inst->hfi_rc_type;
+	u32 hfi_val;
+
+	if (rc_type != HFI_RC_CBR_VFR &&
+	    rc_type != HFI_RC_CBR_CFR)
+		return -EINVAL;
+
+	hfi_val = inst->fw_caps[cap_id].value;
+
+	return hfi_ops->session_set_property(inst, hfi_id,
+					     HFI_HOST_FLAGS_NONE,
+					     iris_get_port_info(inst, cap_id),
+					     HFI_PAYLOAD_U32,
+					     &hfi_val, sizeof(u32));
+}
+
 int iris_set_properties(struct iris_inst *inst, u32 plane)
 {
 	const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops;
diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.h b/drivers/media/platform/qcom/iris/iris_ctrls.h
index 3c462ec9190b..16939e31c784 100644
--- a/drivers/media/platform/qcom/iris/iris_ctrls.h
+++ b/drivers/media/platform/qcom/iris/iris_ctrls.h
@@ -47,6 +47,7 @@ int iris_set_layer_type(struct iris_inst *inst, enum platform_inst_fw_cap_type c
 int iris_set_layer_count_gen1(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id);
 int iris_set_layer_count_gen2(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id);
 int iris_set_layer_bitrate(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id);
+int iris_set_vbv_delay(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id);
 int iris_set_properties(struct iris_inst *inst, u32 plane);
 
 #endif
diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
index 45a418fde7e9..716947f256f1 100644
--- a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
+++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
@@ -944,7 +944,17 @@ static const struct platform_inst_fw_cap inst_fw_cap_sm8550_enc[] = {
 		.flags = CAP_FLAG_OUTPUT_PORT | CAP_FLAG_INPUT_PORT |
 			CAP_FLAG_DYNAMIC_ALLOWED,
 		.set = iris_set_layer_bitrate,
-	}
+	},
+	{
+		.cap_id = VBV_DELAY,
+		.min = 34,
+		.max = 300,
+		.step_or_mask = 1,
+		.value = 300,
+		.hfi_id = HFI_PROP_VBV_DELAY,
+		.flags = CAP_FLAG_OUTPUT_PORT,
+		.set = iris_set_vbv_delay,
+	},
 };
 
 static const u32 sm8550_vdec_input_config_params_default[] = {
diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h b/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h
index 776b21cd11b2..19d04981cdb9 100644
--- a/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h
+++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h
@@ -127,6 +127,7 @@ enum hfi_flip {
 #define HFI_PROP_BUFFER_MARK			0x0300016c
 #define HFI_PROP_WORST_COMPRESSION_RATIO	0x03000174
 #define HFI_PROP_WORST_COMPLEXITY_FACTOR	0x03000175
+#define HFI_PROP_VBV_DELAY			0x03000176
 #define HFI_PROP_RAW_RESOLUTION		0x03000178
 #define HFI_PROP_TOTAL_PEAK_BITRATE		0x0300017C
 #define HFI_PROP_AV1_FILM_GRAIN_PRESENT	0x03000180
diff --git a/drivers/media/platform/qcom/iris/iris_platform_common.h b/drivers/media/platform/qcom/iris/iris_platform_common.h
index c9256f2323dc..a533740ced7c 100644
--- a/drivers/media/platform/qcom/iris/iris_platform_common.h
+++ b/drivers/media/platform/qcom/iris/iris_platform_common.h
@@ -183,6 +183,7 @@ enum platform_inst_fw_cap_type {
 	LAYER3_BITRATE_HEVC,
 	LAYER4_BITRATE_HEVC,
 	LAYER5_BITRATE_HEVC,
+	VBV_DELAY,
 	INST_FW_CAP_MAX,
 };
 

-- 
2.34.1

[PATCH v3 0/2] media: iris: add vbv delay support

[Sachin Kumar Garg]

This series adds VBV_DELAY (V4L2_CID_MPEG_VIDEO_VBV_DELAY) support
for Qualcomm iris encoder sessions, allowing users to configure the
initial VBV (Video Buffer Verifier) delay for CBR-encoded streams.
This is useful for latency-sensitive encoding use cases (e.g.
low-latency streaming) where the client needs explicit control over
the encoder's buffering delay.

Patch 1 is a prerequisite for patch 2. The PIPE capability (control
over the number of VPP hardware pipes used for a session) was
previously only wired up for decoder sessions. Achieving low VBV delay
values (34-100 ms) requires the encoder to be constrained to a single
VPP pipe, so patch 1 enables the PIPE capability on the encoder path as
well, which patch 2 then relies on to force single-pipe operation when
VBV delay falls in that low-latency range.

Patch 2 adds the VBV_DELAY capability: it registers HFI_PROP_VBV_DELAY,
wires up the V4L2_CID_MPEG_VIDEO_VBV_DELAY control for the gen2
encoder, and only applies the property when rate control is set to CBR
since VBV delay is only meaningful for constant-bitrate encoding.
It adds vbv_delay support for iris HFI Gen2 based targets (qcs8300,
sm8550, sm8650, sm8750, x1p42100). Support for HFI Gen1 targets will
be added in a follow-up series.

This series has been verified with GST level testing.
Command used:
gst-launch-1.0 -v videotestsrc ! video/x-raw,format=NV12, \
width=1280,height=720,framerate=30/1 ! v4l2h264enc output-io-mode=4 \
capture-io-mode=4 extra-controls="controls,video_bitrate_mode=1, \
initial_delay_for_vbv_control=300;" ! filesink location=/opt/test_enc.h264

Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
---
Changes in v3:
- iris_set_pipe(): check fw_caps[BITRATE_MODE].value directly instead of
  inst->hfi_rc_type, which is stale here since BITRATE_MODE is applied
  after PIPE in platform_inst_fw_cap_type order.
- Link to v2: https://lore.kernel.org/r/20260926-iris_vbv_delay-v2-0-83dd80765dee@oss.qualcomm.com

Changes in v2:
- iris_set_pipe(): use inclusive VBV_DELAY bounds (>= 34 && <= 100 ms)
  matching the documented range.
- iris_set_pipe(): only force single-pipe under CBR rate control so
  a stale in-range VBV_DELAY no longer affects non-CBR streams.
- iris_set_pipe(): read fw_caps[VBV_DELAY].value once instead of
  twice in the same condition, and derive the default work_route from
  the immutable fw_caps[PIPE].max instead of the self-mutated .value,
  writing the final decision back into .value so frequency scaling
  picks up the corrected pipe count instead of a stale one.
- iris_set_vbv_delay(): drop the dev_err() logged for non-CBR rate
  control; that is an expected, valid configuration, not an error.
- Link to v1: https://lore.kernel.org/r/20260730-iris_vbv_delay-v1-0-7b5a7953bcdf@oss.qualcomm.com

---
Sachin Kumar Garg (2):
      media: iris: enable pipe for hfi gen2 encoder
      media: iris: add support for vbv delay

 drivers/media/platform/qcom/iris/iris_ctrls.c      | 52 ++++++++++++++++++++--
 drivers/media/platform/qcom/iris/iris_ctrls.h      |  1 +
 drivers/media/platform/qcom/iris/iris_hfi_gen2.c   | 19 +++++++-
 .../platform/qcom/iris/iris_hfi_gen2_defines.h     |  1 +
 .../platform/qcom/iris/iris_platform_common.h      |  1 +
 5 files changed, 69 insertions(+), 5 deletions(-)
---
base-commit: a52e6f7923c17a672135b485ffd96fbd72f46267
change-id: 20260730-iris_vbv_delay-343d2fa30842

Best regards,
-- 
Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>

[PATCH v3 1/2] media: iris: enable pipe for hfi gen2 encoder

[Sachin Kumar Garg]

Currently the PIPE capability (HFI_PROP_PIPE / work-route) is only
wired up for the HFI Gen2 decoder. Add a PIPE entry to the HFI Gen2
encoder instance capability table, and extend the encoder
branch of iris_session_init_caps() to derive PIPE's min/max/value
from the platform's num_vpp_pipe, mirroring the existing decoder
handling.

Reviewed-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
---
 drivers/media/platform/qcom/iris/iris_ctrls.c    | 16 +++++++++++++---
 drivers/media/platform/qcom/iris/iris_hfi_gen2.c |  7 +++++++
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.c b/drivers/media/platform/qcom/iris/iris_ctrls.c
index 10e33b8a73f6..33114d80aa68 100644
--- a/drivers/media/platform/qcom/iris/iris_ctrls.c
+++ b/drivers/media/platform/qcom/iris/iris_ctrls.c
@@ -453,13 +453,23 @@ void iris_session_init_caps(struct iris_core *core)
 			continue;
 
 		core->inst_fw_caps_enc[cap_id].cap_id = caps[i].cap_id;
-		core->inst_fw_caps_enc[cap_id].min = caps[i].min;
-		core->inst_fw_caps_enc[cap_id].max = caps[i].max;
 		core->inst_fw_caps_enc[cap_id].step_or_mask = caps[i].step_or_mask;
-		core->inst_fw_caps_enc[cap_id].value = caps[i].value;
 		core->inst_fw_caps_enc[cap_id].flags = caps[i].flags;
 		core->inst_fw_caps_enc[cap_id].hfi_id = caps[i].hfi_id;
 		core->inst_fw_caps_enc[cap_id].set = caps[i].set;
+
+		if (cap_id == PIPE) {
+			core->inst_fw_caps_enc[cap_id].value =
+				core->iris_platform_data->num_vpp_pipe;
+			core->inst_fw_caps_enc[cap_id].min =
+				core->iris_platform_data->num_vpp_pipe;
+			core->inst_fw_caps_enc[cap_id].max =
+				core->iris_platform_data->num_vpp_pipe;
+		} else {
+			core->inst_fw_caps_enc[cap_id].min = caps[i].min;
+			core->inst_fw_caps_enc[cap_id].max = caps[i].max;
+			core->inst_fw_caps_enc[cap_id].value = caps[i].value;
+		}
 	}
 }
 
diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
index acc0ed8adda1..45a418fde7e9 100644
--- a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
+++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
@@ -365,6 +365,13 @@ static const struct platform_inst_fw_cap inst_fw_cap_sm8550_enc[] = {
 		.hfi_id = HFI_PROP_STAGE,
 		.set = iris_set_stage,
 	},
+	{
+		.cap_id = PIPE,
+		/* .max, .min and .value are set via platform data */
+		.step_or_mask = 1,
+		.hfi_id = HFI_PROP_PIPE,
+		.set = iris_set_pipe,
+	},
 	{
 		.cap_id = HEADER_MODE,
 		.min = V4L2_MPEG_VIDEO_HEADER_MODE_SEPARATE,

-- 
2.34.1

[PATCH v3 2/2] media: iris: add support for vbv delay

[Sachin Kumar Garg]

Add the VBV_DELAY instance capability for the HFI Gen2 encoder,
exposed to userspace via V4L2_CID_MPEG_VIDEO_VBV_DELAY and mapped to
HFI_PROP_VBV_DELAY through a new iris_set_vbv_delay(). The property
is only meaningful for CBR rate-control modes.

Low VBV delay values (34-100 ms) require the encoder to run
with a single video pipe, so extend iris_set_pipe() to force
work_route to 1 whenever the configured VBV_DELAY falls in that
range.

Reviewed-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
---
 drivers/media/platform/qcom/iris/iris_ctrls.c      | 36 +++++++++++++++++++++-
 drivers/media/platform/qcom/iris/iris_ctrls.h      |  1 +
 drivers/media/platform/qcom/iris/iris_hfi_gen2.c   | 12 +++++++-
 .../platform/qcom/iris/iris_hfi_gen2_defines.h     |  1 +
 .../platform/qcom/iris/iris_platform_common.h      |  1 +
 5 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.c b/drivers/media/platform/qcom/iris/iris_ctrls.c
index 33114d80aa68..de216661a477 100644
--- a/drivers/media/platform/qcom/iris/iris_ctrls.c
+++ b/drivers/media/platform/qcom/iris/iris_ctrls.c
@@ -154,6 +154,8 @@ static enum platform_inst_fw_cap_type iris_get_cap_id(u32 id)
 		return LAYER4_BITRATE_HEVC;
 	case V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L5_BR:
 		return LAYER5_BITRATE_HEVC;
+	case V4L2_CID_MPEG_VIDEO_VBV_DELAY:
+		return VBV_DELAY;
 	default:
 		return INST_FW_CAP_MAX;
 	}
@@ -297,6 +299,8 @@ static u32 iris_get_v4l2_id(enum platform_inst_fw_cap_type cap_id)
 		return V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L4_BR;
 	case LAYER5_BITRATE_HEVC:
 		return V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L5_BR;
+	case VBV_DELAY:
+		return V4L2_CID_MPEG_VIDEO_VBV_DELAY;
 	default:
 		return 0;
 	}
@@ -541,8 +545,18 @@ int iris_set_stage(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id
 int iris_set_pipe(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id)
 {
 	const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops;
-	u32 work_route = inst->fw_caps[PIPE].value;
+	u32 work_route = inst->fw_caps[PIPE].max;
 	u32 hfi_id = inst->fw_caps[cap_id].hfi_id;
+	u32 vbv_delay;
+
+	if (inst->domain == ENCODER &&
+	    inst->fw_caps[BITRATE_MODE].value == V4L2_MPEG_VIDEO_BITRATE_MODE_CBR) {
+		vbv_delay = inst->fw_caps[VBV_DELAY].value;
+		if (vbv_delay >= 34 && vbv_delay <= 100)
+			work_route = 1;
+	}
+
+	inst->fw_caps[PIPE].value = work_route;
 
 	return hfi_ops->session_set_property(inst, hfi_id,
 					     HFI_HOST_FLAGS_NONE,
@@ -1487,6 +1501,26 @@ int iris_set_layer_bitrate(struct iris_inst *inst, enum platform_inst_fw_cap_typ
 					     &bitrate, sizeof(u32));
 }
 
+int iris_set_vbv_delay(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id)
+{
+	const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops;
+	u32 hfi_id = inst->fw_caps[cap_id].hfi_id;
+	u32 rc_type = inst->hfi_rc_type;
+	u32 hfi_val;
+
+	if (rc_type != HFI_RC_CBR_VFR &&
+	    rc_type != HFI_RC_CBR_CFR)
+		return -EINVAL;
+
+	hfi_val = inst->fw_caps[cap_id].value;
+
+	return hfi_ops->session_set_property(inst, hfi_id,
+					     HFI_HOST_FLAGS_NONE,
+					     iris_get_port_info(inst, cap_id),
+					     HFI_PAYLOAD_U32,
+					     &hfi_val, sizeof(u32));
+}
+
 int iris_set_properties(struct iris_inst *inst, u32 plane)
 {
 	const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops;
diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.h b/drivers/media/platform/qcom/iris/iris_ctrls.h
index 3c462ec9190b..16939e31c784 100644
--- a/drivers/media/platform/qcom/iris/iris_ctrls.h
+++ b/drivers/media/platform/qcom/iris/iris_ctrls.h
@@ -47,6 +47,7 @@ int iris_set_layer_type(struct iris_inst *inst, enum platform_inst_fw_cap_type c
 int iris_set_layer_count_gen1(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id);
 int iris_set_layer_count_gen2(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id);
 int iris_set_layer_bitrate(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id);
+int iris_set_vbv_delay(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id);
 int iris_set_properties(struct iris_inst *inst, u32 plane);
 
 #endif
diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
index 45a418fde7e9..716947f256f1 100644
--- a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
+++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
@@ -944,7 +944,17 @@ static const struct platform_inst_fw_cap inst_fw_cap_sm8550_enc[] = {
 		.flags = CAP_FLAG_OUTPUT_PORT | CAP_FLAG_INPUT_PORT |
 			CAP_FLAG_DYNAMIC_ALLOWED,
 		.set = iris_set_layer_bitrate,
-	}
+	},
+	{
+		.cap_id = VBV_DELAY,
+		.min = 34,
+		.max = 300,
+		.step_or_mask = 1,
+		.value = 300,
+		.hfi_id = HFI_PROP_VBV_DELAY,
+		.flags = CAP_FLAG_OUTPUT_PORT,
+		.set = iris_set_vbv_delay,
+	},
 };
 
 static const u32 sm8550_vdec_input_config_params_default[] = {
diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h b/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h
index 776b21cd11b2..19d04981cdb9 100644
--- a/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h
+++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h
@@ -127,6 +127,7 @@ enum hfi_flip {
 #define HFI_PROP_BUFFER_MARK			0x0300016c
 #define HFI_PROP_WORST_COMPRESSION_RATIO	0x03000174
 #define HFI_PROP_WORST_COMPLEXITY_FACTOR	0x03000175
+#define HFI_PROP_VBV_DELAY			0x03000176
 #define HFI_PROP_RAW_RESOLUTION		0x03000178
 #define HFI_PROP_TOTAL_PEAK_BITRATE		0x0300017C
 #define HFI_PROP_AV1_FILM_GRAIN_PRESENT	0x03000180
diff --git a/drivers/media/platform/qcom/iris/iris_platform_common.h b/drivers/media/platform/qcom/iris/iris_platform_common.h
index c9256f2323dc..a533740ced7c 100644
--- a/drivers/media/platform/qcom/iris/iris_platform_common.h
+++ b/drivers/media/platform/qcom/iris/iris_platform_common.h
@@ -183,6 +183,7 @@ enum platform_inst_fw_cap_type {
 	LAYER3_BITRATE_HEVC,
 	LAYER4_BITRATE_HEVC,
 	LAYER5_BITRATE_HEVC,
+	VBV_DELAY,
 	INST_FW_CAP_MAX,
 };
 

-- 
2.34.1

[PATCH v4 0/2] media: iris: add vbv delay support

[Sachin Kumar Garg]

This series adds VBV_DELAY (V4L2_CID_MPEG_VIDEO_VBV_DELAY) support
for Qualcomm iris encoder sessions, allowing users to configure the
initial VBV (Video Buffer Verifier) delay for CBR-encoded streams.
This is useful for latency-sensitive encoding use cases (e.g.
low-latency streaming) where the client needs explicit control over
the encoder's buffering delay.

Patch 1 is a prerequisite for patch 2. The PIPE capability (control
over the number of VPP hardware pipes used for a session) was
previously only wired up for decoder sessions. Achieving low VBV delay
values (34-100 ms) requires the encoder to be constrained to a single
VPP pipe, so patch 1 enables the PIPE capability on the encoder path as
well, which patch 2 then relies on to force single-pipe operation when
VBV delay falls in that low-latency range.

Patch 2 adds the VBV_DELAY capability: it registers HFI_PROP_VBV_DELAY,
wires up the V4L2_CID_MPEG_VIDEO_VBV_DELAY control for the gen2
encoder, and only applies the property when rate control is set to CBR
since VBV delay is only meaningful for constant-bitrate encoding.
It adds vbv_delay support for iris HFI Gen2 based targets (qcs8300,
sm8550, sm8650, sm8750, x1p42100). Support for HFI Gen1 targets will
be added in a follow-up series.

This series has been verified with GST level testing.
Command used:
gst-launch-1.0 -v videotestsrc ! video/x-raw,format=NV12, \
width=1280,height=720,framerate=30/1 ! v4l2h264enc output-io-mode=4 \
capture-io-mode=4 extra-controls="controls,video_bitrate_mode=1, \
initial_delay_for_vbv_control=300;" ! filesink location=/opt/test_enc.h264

Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
---
Changes in v4:
- iris_set_pipe(): also require fw_caps[FRAME_RC_ENABLE].value before
  forcing single-pipe, since disabling rate control makes the bitrate
  mode (and VBV delay) meaningless regardless of CBR/VBR selection.
- Link to v3: https://lore.kernel.org/r/20260926-iris_vbv_delay-v3-0-d6894f117be5@oss.qualcomm.com

Changes in v3:
- iris_set_pipe(): check fw_caps[BITRATE_MODE].value directly instead of
  inst->hfi_rc_type, which is stale here since BITRATE_MODE is applied
  after PIPE in platform_inst_fw_cap_type order.
- Link to v2: https://lore.kernel.org/r/20260926-iris_vbv_delay-v2-0-83dd80765dee@oss.qualcomm.com

Changes in v2:
- iris_set_pipe(): use inclusive VBV_DELAY bounds (>= 34 && <= 100 ms)
  matching the documented range.
- iris_set_pipe(): only force single-pipe under CBR rate control so
  a stale in-range VBV_DELAY no longer affects non-CBR streams.
- iris_set_pipe(): read fw_caps[VBV_DELAY].value once instead of
  twice in the same condition, and derive the default work_route from
  the immutable fw_caps[PIPE].max instead of the self-mutated .value,
  writing the final decision back into .value so frequency scaling
  picks up the corrected pipe count instead of a stale one.
- iris_set_vbv_delay(): drop the dev_err() logged for non-CBR rate
  control; that is an expected, valid configuration, not an error.
- Link to v1: https://lore.kernel.org/r/20260730-iris_vbv_delay-v1-0-7b5a7953bcdf@oss.qualcomm.com

---
Sachin Kumar Garg (2):
      media: iris: enable pipe for hfi gen2 encoder
      media: iris: add support for vbv delay

 drivers/media/platform/qcom/iris/iris_ctrls.c      | 53 ++++++++++++++++++++--
 drivers/media/platform/qcom/iris/iris_ctrls.h      |  1 +
 drivers/media/platform/qcom/iris/iris_hfi_gen2.c   | 19 +++++++-
 .../platform/qcom/iris/iris_hfi_gen2_defines.h     |  1 +
 .../platform/qcom/iris/iris_platform_common.h      |  1 +
 5 files changed, 70 insertions(+), 5 deletions(-)
---
base-commit: a52e6f7923c17a672135b485ffd96fbd72f46267
change-id: 20260730-iris_vbv_delay-343d2fa30842

Best regards,
-- 
Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>

[PATCH v4 1/2] media: iris: enable pipe for hfi gen2 encoder

[Sachin Kumar Garg]

Currently the PIPE capability (HFI_PROP_PIPE / work-route) is only
wired up for the HFI Gen2 decoder. Add a PIPE entry to the HFI Gen2
encoder instance capability table, and extend the encoder
branch of iris_session_init_caps() to derive PIPE's min/max/value
from the platform's num_vpp_pipe, mirroring the existing decoder
handling.

Reviewed-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
---
 drivers/media/platform/qcom/iris/iris_ctrls.c    | 16 +++++++++++++---
 drivers/media/platform/qcom/iris/iris_hfi_gen2.c |  7 +++++++
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.c b/drivers/media/platform/qcom/iris/iris_ctrls.c
index 10e33b8a73f6..33114d80aa68 100644
--- a/drivers/media/platform/qcom/iris/iris_ctrls.c
+++ b/drivers/media/platform/qcom/iris/iris_ctrls.c
@@ -453,13 +453,23 @@ void iris_session_init_caps(struct iris_core *core)
 			continue;
 
 		core->inst_fw_caps_enc[cap_id].cap_id = caps[i].cap_id;
-		core->inst_fw_caps_enc[cap_id].min = caps[i].min;
-		core->inst_fw_caps_enc[cap_id].max = caps[i].max;
 		core->inst_fw_caps_enc[cap_id].step_or_mask = caps[i].step_or_mask;
-		core->inst_fw_caps_enc[cap_id].value = caps[i].value;
 		core->inst_fw_caps_enc[cap_id].flags = caps[i].flags;
 		core->inst_fw_caps_enc[cap_id].hfi_id = caps[i].hfi_id;
 		core->inst_fw_caps_enc[cap_id].set = caps[i].set;
+
+		if (cap_id == PIPE) {
+			core->inst_fw_caps_enc[cap_id].value =
+				core->iris_platform_data->num_vpp_pipe;
+			core->inst_fw_caps_enc[cap_id].min =
+				core->iris_platform_data->num_vpp_pipe;
+			core->inst_fw_caps_enc[cap_id].max =
+				core->iris_platform_data->num_vpp_pipe;
+		} else {
+			core->inst_fw_caps_enc[cap_id].min = caps[i].min;
+			core->inst_fw_caps_enc[cap_id].max = caps[i].max;
+			core->inst_fw_caps_enc[cap_id].value = caps[i].value;
+		}
 	}
 }
 
diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
index acc0ed8adda1..45a418fde7e9 100644
--- a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
+++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
@@ -365,6 +365,13 @@ static const struct platform_inst_fw_cap inst_fw_cap_sm8550_enc[] = {
 		.hfi_id = HFI_PROP_STAGE,
 		.set = iris_set_stage,
 	},
+	{
+		.cap_id = PIPE,
+		/* .max, .min and .value are set via platform data */
+		.step_or_mask = 1,
+		.hfi_id = HFI_PROP_PIPE,
+		.set = iris_set_pipe,
+	},
 	{
 		.cap_id = HEADER_MODE,
 		.min = V4L2_MPEG_VIDEO_HEADER_MODE_SEPARATE,

-- 
2.34.1

Re: [PATCH v4 1/2] media: iris: enable pipe for hfi gen2 encoder

[Dmitry Baryshkov]

On Sun, Sep 27, 2026 at 09:27:45AM +0530, Sachin Kumar Garg wrote:
> Currently the PIPE capability (HFI_PROP_PIPE / work-route) is only
> wired up for the HFI Gen2 decoder. Add a PIPE entry to the HFI Gen2
> encoder instance capability table, and extend the encoder
> branch of iris_session_init_caps() to derive PIPE's min/max/value
> from the platform's num_vpp_pipe, mirroring the existing decoder
> handling.
> 
> Reviewed-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
> Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
> ---
>  drivers/media/platform/qcom/iris/iris_ctrls.c    | 16 +++++++++++++---
>  drivers/media/platform/qcom/iris/iris_hfi_gen2.c |  7 +++++++
>  2 files changed, 20 insertions(+), 3 deletions(-)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

Nit: it's strongly recommended to send new iterations of the series as a
new thread instead of sending it as a reply to the previous iteration.

-- 
With best wishes
Dmitry

[PATCH v4 2/2] media: iris: add support for vbv delay

[Sachin Kumar Garg]

Add the VBV_DELAY instance capability for the HFI Gen2 encoder,
exposed to userspace via V4L2_CID_MPEG_VIDEO_VBV_DELAY and mapped to
HFI_PROP_VBV_DELAY through a new iris_set_vbv_delay(). The property
is only meaningful for CBR rate-control modes.

Low VBV delay values (34-100 ms) require the encoder to run
with a single video pipe, so extend iris_set_pipe() to force
work_route to 1 whenever the configured VBV_DELAY falls in that
range.

Reviewed-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
---
 drivers/media/platform/qcom/iris/iris_ctrls.c      | 37 +++++++++++++++++++++-
 drivers/media/platform/qcom/iris/iris_ctrls.h      |  1 +
 drivers/media/platform/qcom/iris/iris_hfi_gen2.c   | 12 ++++++-
 .../platform/qcom/iris/iris_hfi_gen2_defines.h     |  1 +
 .../platform/qcom/iris/iris_platform_common.h      |  1 +
 5 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.c b/drivers/media/platform/qcom/iris/iris_ctrls.c
index 33114d80aa68..758c1e77de3f 100644
--- a/drivers/media/platform/qcom/iris/iris_ctrls.c
+++ b/drivers/media/platform/qcom/iris/iris_ctrls.c
@@ -154,6 +154,8 @@ static enum platform_inst_fw_cap_type iris_get_cap_id(u32 id)
 		return LAYER4_BITRATE_HEVC;
 	case V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L5_BR:
 		return LAYER5_BITRATE_HEVC;
+	case V4L2_CID_MPEG_VIDEO_VBV_DELAY:
+		return VBV_DELAY;
 	default:
 		return INST_FW_CAP_MAX;
 	}
@@ -297,6 +299,8 @@ static u32 iris_get_v4l2_id(enum platform_inst_fw_cap_type cap_id)
 		return V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L4_BR;
 	case LAYER5_BITRATE_HEVC:
 		return V4L2_CID_MPEG_VIDEO_HEVC_HIER_CODING_L5_BR;
+	case VBV_DELAY:
+		return V4L2_CID_MPEG_VIDEO_VBV_DELAY;
 	default:
 		return 0;
 	}
@@ -541,8 +545,19 @@ int iris_set_stage(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id
 int iris_set_pipe(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id)
 {
 	const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops;
-	u32 work_route = inst->fw_caps[PIPE].value;
+	u32 work_route = inst->fw_caps[PIPE].max;
 	u32 hfi_id = inst->fw_caps[cap_id].hfi_id;
+	u32 vbv_delay;
+
+	if (inst->domain == ENCODER &&
+	    inst->fw_caps[FRAME_RC_ENABLE].value &&
+	    inst->fw_caps[BITRATE_MODE].value == V4L2_MPEG_VIDEO_BITRATE_MODE_CBR) {
+		vbv_delay = inst->fw_caps[VBV_DELAY].value;
+		if (vbv_delay >= 34 && vbv_delay <= 100)
+			work_route = 1;
+	}
+
+	inst->fw_caps[PIPE].value = work_route;
 
 	return hfi_ops->session_set_property(inst, hfi_id,
 					     HFI_HOST_FLAGS_NONE,
@@ -1487,6 +1502,26 @@ int iris_set_layer_bitrate(struct iris_inst *inst, enum platform_inst_fw_cap_typ
 					     &bitrate, sizeof(u32));
 }
 
+int iris_set_vbv_delay(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id)
+{
+	const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops;
+	u32 hfi_id = inst->fw_caps[cap_id].hfi_id;
+	u32 rc_type = inst->hfi_rc_type;
+	u32 hfi_val;
+
+	if (rc_type != HFI_RC_CBR_VFR &&
+	    rc_type != HFI_RC_CBR_CFR)
+		return -EINVAL;
+
+	hfi_val = inst->fw_caps[cap_id].value;
+
+	return hfi_ops->session_set_property(inst, hfi_id,
+					     HFI_HOST_FLAGS_NONE,
+					     iris_get_port_info(inst, cap_id),
+					     HFI_PAYLOAD_U32,
+					     &hfi_val, sizeof(u32));
+}
+
 int iris_set_properties(struct iris_inst *inst, u32 plane)
 {
 	const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops;
diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.h b/drivers/media/platform/qcom/iris/iris_ctrls.h
index 3c462ec9190b..16939e31c784 100644
--- a/drivers/media/platform/qcom/iris/iris_ctrls.h
+++ b/drivers/media/platform/qcom/iris/iris_ctrls.h
@@ -47,6 +47,7 @@ int iris_set_layer_type(struct iris_inst *inst, enum platform_inst_fw_cap_type c
 int iris_set_layer_count_gen1(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id);
 int iris_set_layer_count_gen2(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id);
 int iris_set_layer_bitrate(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id);
+int iris_set_vbv_delay(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id);
 int iris_set_properties(struct iris_inst *inst, u32 plane);
 
 #endif
diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
index 45a418fde7e9..716947f256f1 100644
--- a/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
+++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2.c
@@ -944,7 +944,17 @@ static const struct platform_inst_fw_cap inst_fw_cap_sm8550_enc[] = {
 		.flags = CAP_FLAG_OUTPUT_PORT | CAP_FLAG_INPUT_PORT |
 			CAP_FLAG_DYNAMIC_ALLOWED,
 		.set = iris_set_layer_bitrate,
-	}
+	},
+	{
+		.cap_id = VBV_DELAY,
+		.min = 34,
+		.max = 300,
+		.step_or_mask = 1,
+		.value = 300,
+		.hfi_id = HFI_PROP_VBV_DELAY,
+		.flags = CAP_FLAG_OUTPUT_PORT,
+		.set = iris_set_vbv_delay,
+	},
 };
 
 static const u32 sm8550_vdec_input_config_params_default[] = {
diff --git a/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h b/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h
index 776b21cd11b2..19d04981cdb9 100644
--- a/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h
+++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h
@@ -127,6 +127,7 @@ enum hfi_flip {
 #define HFI_PROP_BUFFER_MARK			0x0300016c
 #define HFI_PROP_WORST_COMPRESSION_RATIO	0x03000174
 #define HFI_PROP_WORST_COMPLEXITY_FACTOR	0x03000175
+#define HFI_PROP_VBV_DELAY			0x03000176
 #define HFI_PROP_RAW_RESOLUTION		0x03000178
 #define HFI_PROP_TOTAL_PEAK_BITRATE		0x0300017C
 #define HFI_PROP_AV1_FILM_GRAIN_PRESENT	0x03000180
diff --git a/drivers/media/platform/qcom/iris/iris_platform_common.h b/drivers/media/platform/qcom/iris/iris_platform_common.h
index c9256f2323dc..a533740ced7c 100644
--- a/drivers/media/platform/qcom/iris/iris_platform_common.h
+++ b/drivers/media/platform/qcom/iris/iris_platform_common.h
@@ -183,6 +183,7 @@ enum platform_inst_fw_cap_type {
 	LAYER3_BITRATE_HEVC,
 	LAYER4_BITRATE_HEVC,
 	LAYER5_BITRATE_HEVC,
+	VBV_DELAY,
 	INST_FW_CAP_MAX,
 };
 

-- 
2.34.1

Re: [PATCH v4 2/2] media: iris: add support for vbv delay

[Dmitry Baryshkov]

On Sun, Sep 27, 2026 at 09:27:46AM +0530, Sachin Kumar Garg wrote:
> Add the VBV_DELAY instance capability for the HFI Gen2 encoder,
> exposed to userspace via V4L2_CID_MPEG_VIDEO_VBV_DELAY and mapped to
> HFI_PROP_VBV_DELAY through a new iris_set_vbv_delay(). The property
> is only meaningful for CBR rate-control modes.
> 
> Low VBV delay values (34-100 ms) require the encoder to run
> with a single video pipe, so extend iris_set_pipe() to force
> work_route to 1 whenever the configured VBV_DELAY falls in that
> range.
> 
> Reviewed-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
> Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
> ---
>  drivers/media/platform/qcom/iris/iris_ctrls.c      | 37 +++++++++++++++++++++-
>  drivers/media/platform/qcom/iris/iris_ctrls.h      |  1 +
>  drivers/media/platform/qcom/iris/iris_hfi_gen2.c   | 12 ++++++-
>  .../platform/qcom/iris/iris_hfi_gen2_defines.h     |  1 +
>  .../platform/qcom/iris/iris_platform_common.h      |  1 +
>  5 files changed, 50 insertions(+), 2 deletions(-)
> 
> @@ -541,8 +545,19 @@ int iris_set_stage(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id
>  int iris_set_pipe(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id)
>  {
>  	const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops;
> -	u32 work_route = inst->fw_caps[PIPE].value;
> +	u32 work_route = inst->fw_caps[PIPE].max;

Why is being set to the max value instead of using the .value?

>  	u32 hfi_id = inst->fw_caps[cap_id].hfi_id;
> +	u32 vbv_delay;
> +
> +	if (inst->domain == ENCODER &&
> +	    inst->fw_caps[FRAME_RC_ENABLE].value &&
> +	    inst->fw_caps[BITRATE_MODE].value == V4L2_MPEG_VIDEO_BITRATE_MODE_CBR) {
> +		vbv_delay = inst->fw_caps[VBV_DELAY].value;
> +		if (vbv_delay >= 34 && vbv_delay <= 100)
> +			work_route = 1;
> +	}
> +
> +	inst->fw_caps[PIPE].value = work_route;
>  
>  	return hfi_ops->session_set_property(inst, hfi_id,
>  					     HFI_HOST_FLAGS_NONE,
-- 
With best wishes
Dmitry

Re: [PATCH v4 2/2] media: iris: add support for vbv delay

[Sachin Kumar Garg]

On 9/27/2026 11:55 PM, Dmitry Baryshkov wrote:
> On Sun, Sep 27, 2026 at 09:27:46AM +0530, Sachin Kumar Garg wrote:
>> Add the VBV_DELAY instance capability for the HFI Gen2 encoder,
>> exposed to userspace via V4L2_CID_MPEG_VIDEO_VBV_DELAY and mapped to
>> HFI_PROP_VBV_DELAY through a new iris_set_vbv_delay(). The property
>> is only meaningful for CBR rate-control modes.
>>
>> Low VBV delay values (34-100 ms) require the encoder to run
>> with a single video pipe, so extend iris_set_pipe() to force
>> work_route to 1 whenever the configured VBV_DELAY falls in that
>> range.
>>
>> Reviewed-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
>> Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
>> ---
>>   drivers/media/platform/qcom/iris/iris_ctrls.c      | 37 +++++++++++++++++++++-
>>   drivers/media/platform/qcom/iris/iris_ctrls.h      |  1 +
>>   drivers/media/platform/qcom/iris/iris_hfi_gen2.c   | 12 ++++++-
>>   .../platform/qcom/iris/iris_hfi_gen2_defines.h     |  1 +
>>   .../platform/qcom/iris/iris_platform_common.h      |  1 +
>>   5 files changed, 50 insertions(+), 2 deletions(-)
>>
>> @@ -541,8 +545,19 @@ int iris_set_stage(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id
>>   int iris_set_pipe(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id)
>>   {
>>   	const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops;
>> -	u32 work_route = inst->fw_caps[PIPE].value;
>> +	u32 work_route = inst->fw_caps[PIPE].max;
> 
> Why is being set to the max value instead of using the .value?
> 

fw_caps[PIPE].min/.max/.value are all seeded from the same platform 
constant (num_vpp_pipe) at init, so .max and .value were interchangeable 
before this patch. This patch now writes the applied pipe count back 
into .value (used elsewhere for power/cycle estimation), which makes 
.value stateful. Since iris_set_pipe() is re-invoked on every resolution 
change while streaming, seeding work_route from .value would let a 
previous single-pipe override persist as the new baseline on the next 
call, even after the VBV-delay/CBR condition no longer applies. Reading 
from .max instead keeps the default pipe count stable and re-evaluates 
the workaround fresh on every call.

Regards,
Sachin>>   	u32 hfi_id = inst->fw_caps[cap_id].hfi_id;
>> +	u32 vbv_delay;
>> +
>> +	if (inst->domain == ENCODER &&
>> +	    inst->fw_caps[FRAME_RC_ENABLE].value &&
>> +	    inst->fw_caps[BITRATE_MODE].value == V4L2_MPEG_VIDEO_BITRATE_MODE_CBR) {
>> +		vbv_delay = inst->fw_caps[VBV_DELAY].value;
>> +		if (vbv_delay >= 34 && vbv_delay <= 100)
>> +			work_route = 1;
>> +	}
>> +
>> +	inst->fw_caps[PIPE].value = work_route;
>>   
>>   	return hfi_ops->session_set_property(inst, hfi_id,
>>   					     HFI_HOST_FLAGS_NONE,

Re: [PATCH v4 2/2] media: iris: add support for vbv delay

[Dmitry Baryshkov]

On Tue, 29 Sept 2026 at 14:54, Sachin Kumar Garg
<sachin.garg@oss.qualcomm.com> wrote:
>
>
>
> On 9/27/2026 11:55 PM, Dmitry Baryshkov wrote:
> > On Sun, Sep 27, 2026 at 09:27:46AM +0530, Sachin Kumar Garg wrote:
> >> Add the VBV_DELAY instance capability for the HFI Gen2 encoder,
> >> exposed to userspace via V4L2_CID_MPEG_VIDEO_VBV_DELAY and mapped to
> >> HFI_PROP_VBV_DELAY through a new iris_set_vbv_delay(). The property
> >> is only meaningful for CBR rate-control modes.
> >>
> >> Low VBV delay values (34-100 ms) require the encoder to run
> >> with a single video pipe, so extend iris_set_pipe() to force
> >> work_route to 1 whenever the configured VBV_DELAY falls in that
> >> range.
> >>
> >> Reviewed-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
> >> Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
> >> ---
> >>   drivers/media/platform/qcom/iris/iris_ctrls.c      | 37 +++++++++++++++++++++-
> >>   drivers/media/platform/qcom/iris/iris_ctrls.h      |  1 +
> >>   drivers/media/platform/qcom/iris/iris_hfi_gen2.c   | 12 ++++++-
> >>   .../platform/qcom/iris/iris_hfi_gen2_defines.h     |  1 +
> >>   .../platform/qcom/iris/iris_platform_common.h      |  1 +
> >>   5 files changed, 50 insertions(+), 2 deletions(-)
> >>
> >> @@ -541,8 +545,19 @@ int iris_set_stage(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id
> >>   int iris_set_pipe(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id)
> >>   {
> >>      const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops;
> >> -    u32 work_route = inst->fw_caps[PIPE].value;
> >> +    u32 work_route = inst->fw_caps[PIPE].max;
> >
> > Why is being set to the max value instead of using the .value?
> >
>
> fw_caps[PIPE].min/.max/.value are all seeded from the same platform
> constant (num_vpp_pipe) at init, so .max and .value were interchangeable
> before this patch. This patch now writes the applied pipe count back
> into .value (used elsewhere for power/cycle estimation), which makes
> .value stateful. Since iris_set_pipe() is re-invoked on every resolution
> change while streaming, seeding work_route from .value would let a
> previous single-pipe override persist as the new baseline on the next
> call, even after the VBV-delay/CBR condition no longer applies. Reading
> from .max instead keeps the default pipe count stable and re-evaluates
> the workaround fresh on every call.

With the .value being written, does it need a lock protection?

>
> Regards,
> Sachin>>        u32 hfi_id = inst->fw_caps[cap_id].hfi_id;
> >> +    u32 vbv_delay;
> >> +
> >> +    if (inst->domain == ENCODER &&
> >> +        inst->fw_caps[FRAME_RC_ENABLE].value &&
> >> +        inst->fw_caps[BITRATE_MODE].value == V4L2_MPEG_VIDEO_BITRATE_MODE_CBR) {
> >> +            vbv_delay = inst->fw_caps[VBV_DELAY].value;
> >> +            if (vbv_delay >= 34 && vbv_delay <= 100)
> >> +                    work_route = 1;
> >> +    }
> >> +
> >> +    inst->fw_caps[PIPE].value = work_route;
> >>
> >>      return hfi_ops->session_set_property(inst, hfi_id,
> >>                                           HFI_HOST_FLAGS_NONE,
>


-- 
With best wishes
Dmitry

Re: [PATCH v4 2/2] media: iris: add support for vbv delay

[Sachin Kumar Garg]

On 9/29/2026 8:35 PM, Dmitry Baryshkov wrote:
> On Tue, 29 Sept 2026 at 14:54, Sachin Kumar Garg
> <sachin.garg@oss.qualcomm.com> wrote:
>>
>>
>>
>> On 9/27/2026 11:55 PM, Dmitry Baryshkov wrote:
>>> On Sun, Sep 27, 2026 at 09:27:46AM +0530, Sachin Kumar Garg wrote:
>>>> Add the VBV_DELAY instance capability for the HFI Gen2 encoder,
>>>> exposed to userspace via V4L2_CID_MPEG_VIDEO_VBV_DELAY and mapped to
>>>> HFI_PROP_VBV_DELAY through a new iris_set_vbv_delay(). The property
>>>> is only meaningful for CBR rate-control modes.
>>>>
>>>> Low VBV delay values (34-100 ms) require the encoder to run
>>>> with a single video pipe, so extend iris_set_pipe() to force
>>>> work_route to 1 whenever the configured VBV_DELAY falls in that
>>>> range.
>>>>
>>>> Reviewed-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
>>>> Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
>>>> ---
>>>>    drivers/media/platform/qcom/iris/iris_ctrls.c      | 37 +++++++++++++++++++++-
>>>>    drivers/media/platform/qcom/iris/iris_ctrls.h      |  1 +
>>>>    drivers/media/platform/qcom/iris/iris_hfi_gen2.c   | 12 ++++++-
>>>>    .../platform/qcom/iris/iris_hfi_gen2_defines.h     |  1 +
>>>>    .../platform/qcom/iris/iris_platform_common.h      |  1 +
>>>>    5 files changed, 50 insertions(+), 2 deletions(-)
>>>>
>>>> @@ -541,8 +545,19 @@ int iris_set_stage(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id
>>>>    int iris_set_pipe(struct iris_inst *inst, enum platform_inst_fw_cap_type cap_id)
>>>>    {
>>>>       const struct iris_hfi_session_ops *hfi_ops = inst->hfi_session_ops;
>>>> -    u32 work_route = inst->fw_caps[PIPE].value;
>>>> +    u32 work_route = inst->fw_caps[PIPE].max;
>>>
>>> Why is being set to the max value instead of using the .value?
>>>
>>
>> fw_caps[PIPE].min/.max/.value are all seeded from the same platform
>> constant (num_vpp_pipe) at init, so .max and .value were interchangeable
>> before this patch. This patch now writes the applied pipe count back
>> into .value (used elsewhere for power/cycle estimation), which makes
>> .value stateful. Since iris_set_pipe() is re-invoked on every resolution
>> change while streaming, seeding work_route from .value would let a
>> previous single-pipe override persist as the new baseline on the next
>> call, even after the VBV-delay/CBR condition no longer applies. Reading
>> from .max instead keeps the default pipe count stable and re-evaluates
>> the workaround fresh on every call.
> 
> With the .value being written, does it need a lock protection?
> 
No — inst->lock already serializes this. iris_set_pipe()'s write to 
fw_caps[PIPE].value only happens inside start_streaming 
(iris_venc/vdec_streamon_output(), both the iris_set_properties() cap 
loop and the DRC re-apply path), and start_streaming takes inst->lock 
before reaching either. The only reader outside that same call chain is 
the power/clock-scaling code (iris_vpu3x_vpu4x_calculate_frequency()), 
which is only invoked via iris_scale_power(), itself called from 
start_streaming and buf_queue — both of which also hold inst->lock. So 
writer and readers already can't run concurrently; adding a lock here 
would just be redundant with the existing vb2-op locking, and no other 
.set() callback in this file takes one either.

Regards,
Sachin>>
>> Regards,
>> Sachin>>        u32 hfi_id = inst->fw_caps[cap_id].hfi_id;
>>>> +    u32 vbv_delay;
>>>> +
>>>> +    if (inst->domain == ENCODER &&
>>>> +        inst->fw_caps[FRAME_RC_ENABLE].value &&
>>>> +        inst->fw_caps[BITRATE_MODE].value == V4L2_MPEG_VIDEO_BITRATE_MODE_CBR) {
>>>> +            vbv_delay = inst->fw_caps[VBV_DELAY].value;
>>>> +            if (vbv_delay >= 34 && vbv_delay <= 100)
>>>> +                    work_route = 1;
>>>> +    }
>>>> +
>>>> +    inst->fw_caps[PIPE].value = work_route;
>>>>
>>>>       return hfi_ops->session_set_property(inst, hfi_id,
>>>>                                            HFI_HOST_FLAGS_NONE,
>>
> 
>