Re: [PATCH] Add support for multi_slice in iris encoder

[Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>]

On 6/26/2026 5:58 PM, Vikash Garodia wrote:
> 
> On 4/28/2026 12:44 PM, Sachin Kumar Garg wrote:
>> Add multi-slice encoding support with MAX_MB and MAX_BYTES modes.
>>
>> Clients can enable slice mode using V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MODE
>> control and configure slice size via 
>> V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MAX_MB
>> or V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MAX_BYTES controls.
>>
>> Signed-off-by: Sachin Kumar Garg <sachin.garg@oss.qualcomm.com>
>> ---
>> This series adds the support for multi slice feature in the
> 
> series ?
> 
>> Qualcomm Iris driver.
>>
>> Multi-slice mode allows encoding a single frame into multiple slices,
>> which can improve error resilience and enable parallel processing.
>> The feature supports two slice modes:
>> - MAX_MB mode: Slices are created based on macroblock count, controlled
>>    via V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MAX_MB
>> - MAX_BYTES mode: Slices are created based on byte size, controlled via
>>    V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MAX_BYTES
>>
>> Clients can enable slice mode using the
>> V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MODE control.
>>
>> This series adds multi-slice support for HFI Gen2 targets (SM8550 and 
>> later).
>> Support for HFI Gen1 targets will be added in a follow-up series.
>>
>> This Patch has been verified with GST level.
> 
> specify the platform tested.>

Hi Vikash, updated the platform tested list in v2 posting.

>> 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, \
>> slice_partitioning_method=1,number_of_mbs_in_a_slice=460;" \
>> ! filesink location=/opt/test_enc.h264
>> ---
>>   drivers/media/platform/qcom/iris/iris_ctrls.c      | 89 ++++++++++++ 
>> ++++++++++
>>   drivers/media/platform/qcom/iris/iris_ctrls.h      |  1 +
>>   .../platform/qcom/iris/iris_hfi_gen2_defines.h     |  2 +
>>   .../platform/qcom/iris/iris_platform_common.h      |  3 +
>>   .../media/platform/qcom/iris/iris_platform_gen2.c  | 31 ++++++++
>>   5 files changed, 126 insertions(+)
>>
>> diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.c b/drivers/ 
>> media/platform/qcom/iris/iris_ctrls.c
>> index 3cec957580f5..52b92241e7f0 100644
>> --- a/drivers/media/platform/qcom/iris/iris_ctrls.c
>> +++ b/drivers/media/platform/qcom/iris/iris_ctrls.c
>> @@ -13,6 +13,15 @@
>>   #define CABAC_MAX_BITRATE 160000000
>>   #define CAVLC_MAX_BITRATE 220000000
>> +#define MAX_SLICES_PER_FRAME 10
> 
> can you reconfirm this if this is indeed limited to 10 ?
> 

Hi Vikash, This has been replaced with a
per-platform capability (max_slices_per_frame), currently set to 128.

>> +#define MAX_SLICES_FRAME_RATE 60
>> +#define MAX_MB_SLICE_WIDTH 4096
>> +#define MAX_MB_SLICE_HEIGHT 2160
>> +#define MAX_BYTES_SLICE_WIDTH 1920
>> +#define MAX_BYTES_SLICE_HEIGHT 1088
>> +#define MIN_HEVC_SLICE_WIDTH 384
>> +#define MIN_AVC_SLICE_WIDTH 192
>> +#define MIN_SLICE_HEIGHT 128
>>   static inline bool iris_valid_cap_id(enum platform_inst_fw_cap_type 
>> cap_id)
>>   {
>> @@ -112,6 +121,12 @@ static enum platform_inst_fw_cap_type 
>> iris_get_cap_id(u32 id)
>>           return IR_TYPE;
>>       case V4L2_CID_MPEG_VIDEO_INTRA_REFRESH_PERIOD:
>>           return IR_PERIOD;
>> +    case V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MODE:
>> +        return SLICE_MODE;
>> +    case V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MAX_BYTES:
>> +        return SLICE_MAX_BYTES;
>> +    case V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MAX_MB:
>> +        return SLICE_MAX_MB;
>>       default:
>>           return INST_FW_CAP_MAX;
>>       }
>> @@ -213,6 +228,12 @@ static u32 iris_get_v4l2_id(enum 
>> platform_inst_fw_cap_type cap_id)
>>           return V4L2_CID_MPEG_VIDEO_INTRA_REFRESH_PERIOD_TYPE;
>>       case IR_PERIOD:
>>           return V4L2_CID_MPEG_VIDEO_INTRA_REFRESH_PERIOD;
>> +    case SLICE_MODE:
>> +        return V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MODE;
>> +    case SLICE_MAX_BYTES:
>> +        return V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MAX_BYTES;
>> +    case SLICE_MAX_MB:
>> +        return V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MAX_MB;
>>       default:
>>           return 0;
>>       }
>> @@ -996,6 +1017,74 @@ int iris_set_ir_period(struct iris_inst *inst, 
>> enum platform_inst_fw_cap_type ca
>>                            &ir_period, sizeof(u32));
>>   }
>> +int iris_set_slice_count(struct iris_inst *inst, enum 
>> platform_inst_fw_cap_type cap_id)
>> +{
>> +    const struct iris_hfi_command_ops *hfi_ops = inst->core->hfi_ops;
>> +    u32 slice_mode = inst->fw_caps[SLICE_MODE].value;
>> +    u32 bitrate = inst->fw_caps[BITRATE].value;
>> +    u32 rc_type = inst->fw_caps[BITRATE_MODE].value;
>> +    u32 fps = inst->frame_rate;
>> +    u32 output_width = inst->fmt_dst->fmt.pix_mp.width;
>> +    u32 output_height = inst->fmt_dst->fmt.pix_mp.height;
>> +    u32 mbpf = NUM_MBS_PER_FRAME(output_height, output_width);
>> +    u32 max_width, max_height, min_width, min_height;
>> +    u32 max_avg_slicesize, hfi_value, hfi_id;
>> +
>> +    if (slice_mode == V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_SINGLE) {
>> +        dev_dbg(inst->core->dev, "slice mode is: %u, ignore setting 
>> to fw\n", slice_mode);
>> +        return 0;
>> +    }
>> +    if (!fps) {
>> +        dev_err(inst->core->dev, "Invalid frame rate %d\n", fps);
>> +        return -EINVAL;
>> +    }
>> +    if (fps > MAX_SLICES_FRAME_RATE ||
>> +        (rc_type != HFI_RC_OFF && rc_type != HFI_RC_CBR_CFR &&
>> +        rc_type != HFI_RC_CBR_VFR)) {
>> +        dev_err(inst->core->dev, "slice unsupported, fps: %u, 
>> rc_type: %#x\n",
>> +            fps, rc_type);
>> +        return -EINVAL;
>> +    }
>> +
>> +    max_width = (slice_mode == 
>> V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_MAX_MB) ?
>> +            MAX_MB_SLICE_WIDTH : MAX_BYTES_SLICE_WIDTH;
>> +    max_height = (slice_mode == 
>> V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_MAX_MB) ?
>> +            MAX_MB_SLICE_HEIGHT : MAX_BYTES_SLICE_HEIGHT;
>> +    min_width = (inst->codec == V4L2_PIX_FMT_HEVC) ?
>> +            MIN_HEVC_SLICE_WIDTH : MIN_AVC_SLICE_WIDTH;
>> +    min_height = MIN_SLICE_HEIGHT;
> 
> All these values are made into common setter, if there is a SOC, which 
> supports different capabilities, these need to be redesigned. Can you 
> see on how to make this platform specific capabilities and then make the 
> checks generic to be used for all SOCs ?
> 

Hi Vikash, reworked as suggested. All the slice limits parameters
are now fields on struct platform_inst_caps (iris_platform_common.h),
populated per-SoC in platform files.

>> +
>> +    if (output_width < min_width || output_height < min_height ||
>> +        output_width > max_width || output_height > max_height) {
>> +        dev_err(inst->core->dev, "slice unsupported, codec: %#x wxh: 
>> [%dx%d]\n",
>> +            inst->codec, output_width, output_height);
>> +        return -EINVAL;
>> +    }
>> +
>> +    if (slice_mode == V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_MAX_MB) {
>> +        hfi_value = inst->fw_caps[SLICE_MAX_MB].value;
>> +        hfi_value = max(hfi_value, mbpf / MAX_SLICES_PER_FRAME);
>> +        if (inst->codec == V4L2_PIX_FMT_HEVC)
>> +            hfi_value = (hfi_value + 3) / 4;
>> +        hfi_id = inst->fw_caps[SLICE_MAX_MB].hfi_id;
>> +    } else if (slice_mode == 
>> V4L2_MPEG_VIDEO_MULTI_SLICE_MODE_MAX_BYTES) {
>> +        hfi_value = inst->fw_caps[SLICE_MAX_BYTES].value;
>> +        if (rc_type != HFI_RC_OFF) {
>> +            max_avg_slicesize = ((bitrate / fps) / 8) / 
>> MAX_SLICES_PER_FRAME;
>> +            hfi_value = max(hfi_value, max_avg_slicesize);
>> +        }
>> +        hfi_id = inst->fw_caps[SLICE_MAX_BYTES].hfi_id;
>> +    } else {
>> +        return -EINVAL;
>> +    }
>> +
>> +    return hfi_ops->session_set_property(inst, hfi_id,
>> +                         HFI_HOST_FLAGS_NONE,
>> +                         iris_get_port_info(inst, cap_id),
>> +                         HFI_PAYLOAD_U32,
>> +                         &hfi_value, sizeof(u32));
>> +}
>> +
>>   int iris_set_properties(struct iris_inst *inst, u32 plane)
>>   {
>>       const struct iris_hfi_command_ops *hfi_ops = inst->core->hfi_ops;
>> diff --git a/drivers/media/platform/qcom/iris/iris_ctrls.h b/drivers/ 
>> media/platform/qcom/iris/iris_ctrls.h
>> index 9518803577bc..5280ee00d9a0 100644
>> --- a/drivers/media/platform/qcom/iris/iris_ctrls.h
>> +++ b/drivers/media/platform/qcom/iris/iris_ctrls.h
>> @@ -35,6 +35,7 @@ int iris_set_qp_range(struct iris_inst *inst, enum 
>> platform_inst_fw_cap_type cap
>>   int iris_set_rotation(struct iris_inst *inst, enum 
>> platform_inst_fw_cap_type cap_id);
>>   int iris_set_flip(struct iris_inst *inst, enum 
>> platform_inst_fw_cap_type cap_id);
>>   int iris_set_ir_period(struct iris_inst *inst, enum 
>> platform_inst_fw_cap_type cap_id);
>> +int iris_set_slice_count(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_defines.h 
>> b/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h
>> index cecf771c55dd..8a27f246e114 100644
>> --- a/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h
>> +++ b/drivers/media/platform/qcom/iris/iris_hfi_gen2_defines.h
>> @@ -71,6 +71,8 @@ enum hfi_rate_control {
>>   #define HFI_PROP_MIN_QP_PACKED            0x0300012f
>>   #define HFI_PROP_MAX_QP_PACKED            0x03000130
>>   #define HFI_PROP_IR_RANDOM_PERIOD        0x03000131
>> +#define HFI_PROP_MULTI_SLICE_MB_COUNT        0x03000132
>> +#define HFI_PROP_MULTI_SLICE_BYTES_COUNT    0x03000133
>>   #define HFI_PROP_TOTAL_BITRATE            0x0300013b
>>   #define HFI_PROP_MAX_GOP_FRAMES            0x03000146
>>   #define HFI_PROP_MAX_B_FRAMES            0x03000147
>> diff --git a/drivers/media/platform/qcom/iris/iris_platform_common.h 
>> b/drivers/media/platform/qcom/iris/iris_platform_common.h
>> index 5a489917580e..05962d8fbb25 100644
>> --- a/drivers/media/platform/qcom/iris/iris_platform_common.h
>> +++ b/drivers/media/platform/qcom/iris/iris_platform_common.h
>> @@ -159,6 +159,9 @@ enum platform_inst_fw_cap_type {
>>       VFLIP,
>>       IR_TYPE,
>>       IR_PERIOD,
>> +    SLICE_MODE,
>> +    SLICE_MAX_BYTES,
>> +    SLICE_MAX_MB,
>>       INST_FW_CAP_MAX,
>>   };
>> diff --git a/drivers/media/platform/qcom/iris/iris_platform_gen2.c b/ 
>> drivers/media/platform/qcom/iris/iris_platform_gen2.c
>> index 5da90d47f9c6..191154a8ab8d 100644
>> --- a/drivers/media/platform/qcom/iris/iris_platform_gen2.c
>> +++ b/drivers/media/platform/qcom/iris/iris_platform_gen2.c
>> @@ -18,6 +18,8 @@
>>   #define VIDEO_ARCH_LX 1
>>   #define BITRATE_MAX                245000000
>> +#define MAX_SLICE_MB_SIZE         \
>> +    (((4096 + 15) >> 4) * ((2304 + 15) >> 4))
> 
> Why is 2304 inconsistent with "MAX_MB_SLICE_HEIGHT 2160" ?
> 
> Regards,
> Vikash
> 

Hi Vikash, thanks for pointing out. I have fixed it in v2 posting.

Regards,
Sachin