* [PATCH v2] media: i2c: vd55g1: fix VD55G0 streaming below 900 Mbps
@ 2026-10-16 10:28 George Neacsu via B4 Relay
2026-10-16 11:02 ` Benjamin Mugnier
0 siblings, 1 reply; 3+ messages in thread
From: George Neacsu via B4 Relay @ 2026-10-16 10:28 UTC (permalink / raw)
To: sylvain.petinot, pm, benjamin.mugnier
Cc: sakari.ailus, linux-kernel, mchehab, linux-media, fqwqf, lsa.uz,
George Neacsu
From: George Neacsu <geocausa@gmail.com>
On a Surface Pro 11 (Snapdragon X Elite, CAMSS) the VD55G0 IR sensor
(cut 1, revision 0x1111) runs one D-PHY lane at 840 Mbps. With the
VD55G0 support as posted, the sensor accepts the start command and
reports STREAMING, but it never sends a frame and the stop command
never completes.
The minimum line length is the VD55G1 value, 1128 pixels. ST's
reference vd55g0 driver uses 1200 below 900 Mbps and 1128 above. At
840 Mbps the sensor stalls with 1128 and streams with 1200, so use 1200
for the VD55G0 below 900 Mbps.
With this change the sensor streams 644x604 Y10 at 61.6 fps, the
diagonal grey-scale test pattern comes out correct, and stop completes.
The built-in 2.11 cut1 patch is used unchanged.
Link: https://github.com/STMicroelectronics/vd55g0-linux-driver/blob/a05627b0f6d8775aa54b6fa306e91f425f2cbf9e/vd55g0.c
Assisted-by: Claude:claude-opus-5-5
Signed-off-by: George Neacsu <geocausa@gmail.com>
---
This is an incremental fix for Peter's unmerged VD55G0 support (v2,
patch 11/11), on top of Jizhou's register-width fix (v2). It does not
apply to media-next on its own.
Prerequisites:
https://lore.kernel.org/all/20260918221705.323510-1-pm@petermarshall.ca/
(and Jizhou Tong's "[PATCH v2] media: i2c: vd55g1: correct VD55G0
register access widths", 12 October)
Benjamin, I know you'd rather see a separate vd55g0 driver (Sergey's).
ST's downstream driver also uses a 1200-pixel line below 900 Mbps, so
this is a data point for that driver too. I can test Sergey's driver on
the Snapdragon Surface Pro 11 when it is posted.
Tested on mainline (62f482ff73bf) with Peter's v2 01 and 04-11 plus
Jizhou's fix. 02 and 03 did not apply to that tree, and neither touches
the driver. The receiver is qcom CAMSS (CSIPHY0 -> CSID0 -> VFE0 RDI0)
with out-of-tree Surface Pro 11 board support.
---
Changes in v2:
- Drop the ISL_ENABLE (0x0329) change. Sergey found that writing it
does not stop the output on the Intel model, and a retest here agrees:
with the 1200-pixel line the sensor streams whether 0x0329 is written
at stream start, once per power-on, or not at all.
- Link to v1: https://lore.kernel.org/r/20261016-vd55g0-sp11-fix-v1-1-eb14bd80d8f8@gmail.com
---
drivers/media/i2c/vd55g1.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/media/i2c/vd55g1.c b/drivers/media/i2c/vd55g1.c
index ba70447..4e23e88 100644
--- a/drivers/media/i2c/vd55g1.c
+++ b/drivers/media/i2c/vd55g1.c
@@ -76,6 +76,8 @@
#define VD55G1_XCLK_FREQ_MAX (27 * HZ_PER_MHZ)
#define VD55G0_MIPI_RATE_MIN (750 * MEGA)
#define VD55G0_MIPI_RATE_MAX (1200 * MEGA)
+#define VD55G0_LINE_LENGTH_LOW_RATE 1200
+#define VD55G0_LOW_MIPI_RATE_LIMIT (900 * MEGA)
#define VD55G1_MIPI_RATE_MIN (250 * MEGA)
#define VD55G1_MIPI_RATE_MAX (1200 * MEGA)
@@ -1245,6 +1247,8 @@ struct vd55g1_model {
u16 num_modes;
u32 mipi_rate_min;
u32 mipi_rate_max;
+ u32 low_mipi_rate_limit;
+ u16 line_length_low_rate;
u16 width;
u16 height;
bool bayer;
@@ -1323,6 +1327,8 @@ static const struct vd55g1_model vd55g0_model = {
.num_modes = ARRAY_SIZE(vd55g0_supported_modes),
.mipi_rate_min = VD55G0_MIPI_RATE_MIN,
.mipi_rate_max = VD55G0_MIPI_RATE_MAX,
+ .low_mipi_rate_limit = VD55G0_LOW_MIPI_RATE_LIMIT,
+ .line_length_low_rate = VD55G0_LINE_LENGTH_LOW_RATE,
.width = VD55G0_WIDTH,
.height = VD55G0_HEIGHT,
.bayer = false,
@@ -1542,6 +1548,8 @@ static unsigned int vd55g1_get_hblank_min(struct vd55g1 *sensor,
/* Absolute time required for ADCs to convert pixels */
min_line_length = VD55G1_LINE_LENGTH_MIN;
+ if (sensor->mipi_rate < sensor->model->low_mipi_rate_limit)
+ min_line_length = sensor->model->line_length_low_rate;
if (sensor->model->hdr &&
sensor->hdr_ctrl->val == VD55G1_HDR_SUB)
min_line_length = VD55G1_LINE_LENGTH_SUB_MIN;
---
base-commit: 62f482ff73bf3ae88b0c899115527752cf9cbf13
change-id: 20261016-vd55g0-sp11-fix-60bc64a59b1d
prerequisite-patch-id: d4474f51d7a10cfd10a316ec2b09936490b14a79
prerequisite-patch-id: 0017cc56bf769ab00e67bdc0c5214951447cb716
prerequisite-patch-id: 95a2d9ff8168eb17010538d80f4b5428e2b7b798
prerequisite-patch-id: e717e32eac916ccafccf9e7a552ca0030085daa3
prerequisite-patch-id: 8fc4f7595aac33a2164adb41c139dc3218be5bc6
prerequisite-patch-id: 52bde56940b545c0e5f44d12811f9b9676bc311c
prerequisite-patch-id: c0b93409e330d4b874b3702d67b57e2c4b0bde32
prerequisite-patch-id: dbc6f65015852bbaf31e5f4efbee52c60bafb79f
prerequisite-patch-id: d5c9bb074014a20938df8b55bb9088aa7b26d37b
prerequisite-patch-id: d1ce44a3f9104aeead2c18d58a1470d1bd1ae531
Best regards,
--
George Neacsu <geocausa@gmail.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] media: i2c: vd55g1: fix VD55G0 streaming below 900 Mbps
2026-10-16 10:28 [PATCH v2] media: i2c: vd55g1: fix VD55G0 streaming below 900 Mbps George Neacsu via B4 Relay
@ 2026-10-16 11:02 ` Benjamin Mugnier
2026-10-16 14:55 ` George Neacsu
0 siblings, 1 reply; 3+ messages in thread
From: Benjamin Mugnier @ 2026-10-16 11:02 UTC (permalink / raw)
To: geocausa, sylvain.petinot, pm
Cc: sakari.ailus, linux-kernel, mchehab, linux-media, fqwqf, lsa.uz
Hi George,
Le 16/10/2026 à 12:28, George Neacsu via B4 Relay a écrit :
> From: George Neacsu <geocausa@gmail.com>
>
> On a Surface Pro 11 (Snapdragon X Elite, CAMSS) the VD55G0 IR sensor
> (cut 1, revision 0x1111) runs one D-PHY lane at 840 Mbps. With the
> VD55G0 support as posted, the sensor accepts the start command and
> reports STREAMING, but it never sends a frame and the stop command
> never completes.
>
> The minimum line length is the VD55G1 value, 1128 pixels. ST's
> reference vd55g0 driver uses 1200 below 900 Mbps and 1128 above. At
> 840 Mbps the sensor stalls with 1128 and streams with 1200, so use 1200
> for the VD55G0 below 900 Mbps.
Yes, the downstream driver was designed to work with specific parameters.
>
> With this change the sensor streams 644x604 Y10 at 61.6 fps, the
> diagonal grey-scale test pattern comes out correct, and stop completes.
> The built-in 2.11 cut1 patch is used unchanged.
>
> Link: https://github.com/STMicroelectronics/vd55g0-linux-driver/blob/a05627b0f6d8775aa54b6fa306e91f425f2cbf9e/vd55g0.c
> Assisted-by: Claude:claude-opus-5-5
> Signed-off-by: George Neacsu <geocausa@gmail.com>
> ---
> This is an incremental fix for Peter's unmerged VD55G0 support (v2,
> patch 11/11), on top of Jizhou's register-width fix (v2). It does not
> apply to media-next on its own.
>
> Prerequisites:
> https://lore.kernel.org/all/20260918221705.323510-1-pm@petermarshall.ca/
> (and Jizhou Tong's "[PATCH v2] media: i2c: vd55g1: correct VD55G0
> register access widths", 12 October)
>
> Benjamin, I know you'd rather see a separate vd55g0 driver (Sergey's).
> ST's downstream driver also uses a 1200-pixel line below 900 Mbps, so
> this is a data point for that driver too. I can test Sergey's driver on
> the Snapdragon Surface Pro 11 when it is posted.
We reworked the clock tree with Sergey so it may fix your issue too.
Please test it once it hits the mailing list and we will make required
adjustments.
>
> Tested on mainline (62f482ff73bf) with Peter's v2 01 and 04-11 plus
> Jizhou's fix. 02 and 03 did not apply to that tree, and neither touches
> the driver. The receiver is qcom CAMSS (CSIPHY0 -> CSID0 -> VFE0 RDI0)
> with out-of-tree Surface Pro 11 board support.
> ---
> Changes in v2:
> - Drop the ISL_ENABLE (0x0329) change. Sergey found that writing it
> does not stop the output on the Intel model, and a retest here agrees:
> with the 1200-pixel line the sensor streams whether 0x0329 is written
> at stream start, once per power-on, or not at all.
> - Link to v1: https://lore.kernel.org/r/20261016-vd55g0-sp11-fix-v1-1-eb14bd80d8f8@gmail.com
> ---
> drivers/media/i2c/vd55g1.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/media/i2c/vd55g1.c b/drivers/media/i2c/vd55g1.c
> index ba70447..4e23e88 100644
> --- a/drivers/media/i2c/vd55g1.c
> +++ b/drivers/media/i2c/vd55g1.c
> @@ -76,6 +76,8 @@
> #define VD55G1_XCLK_FREQ_MAX (27 * HZ_PER_MHZ)
> #define VD55G0_MIPI_RATE_MIN (750 * MEGA)
> #define VD55G0_MIPI_RATE_MAX (1200 * MEGA)
> +#define VD55G0_LINE_LENGTH_LOW_RATE 1200
> +#define VD55G0_LOW_MIPI_RATE_LIMIT (900 * MEGA)
> #define VD55G1_MIPI_RATE_MIN (250 * MEGA)
> #define VD55G1_MIPI_RATE_MAX (1200 * MEGA)
>
> @@ -1245,6 +1247,8 @@ struct vd55g1_model {
> u16 num_modes;
> u32 mipi_rate_min;
> u32 mipi_rate_max;
> + u32 low_mipi_rate_limit;
> + u16 line_length_low_rate;
> u16 width;
> u16 height;
> bool bayer;
> @@ -1323,6 +1327,8 @@ static const struct vd55g1_model vd55g0_model = {
> .num_modes = ARRAY_SIZE(vd55g0_supported_modes),
> .mipi_rate_min = VD55G0_MIPI_RATE_MIN,
> .mipi_rate_max = VD55G0_MIPI_RATE_MAX,
> + .low_mipi_rate_limit = VD55G0_LOW_MIPI_RATE_LIMIT,
> + .line_length_low_rate = VD55G0_LINE_LENGTH_LOW_RATE,
> .width = VD55G0_WIDTH,
> .height = VD55G0_HEIGHT,
> .bayer = false,
> @@ -1542,6 +1548,8 @@ static unsigned int vd55g1_get_hblank_min(struct vd55g1 *sensor,
>
> /* Absolute time required for ADCs to convert pixels */
> min_line_length = VD55G1_LINE_LENGTH_MIN;
> + if (sensor->mipi_rate < sensor->model->low_mipi_rate_limit)
> + min_line_length = sensor->model->line_length_low_rate;
> if (sensor->model->hdr &&
> sensor->hdr_ctrl->val == VD55G1_HDR_SUB)
> min_line_length = VD55G1_LINE_LENGTH_SUB_MIN;
>
> ---
> base-commit: 62f482ff73bf3ae88b0c899115527752cf9cbf13
> change-id: 20261016-vd55g0-sp11-fix-60bc64a59b1d
> prerequisite-patch-id: d4474f51d7a10cfd10a316ec2b09936490b14a79
> prerequisite-patch-id: 0017cc56bf769ab00e67bdc0c5214951447cb716
> prerequisite-patch-id: 95a2d9ff8168eb17010538d80f4b5428e2b7b798
> prerequisite-patch-id: e717e32eac916ccafccf9e7a552ca0030085daa3
> prerequisite-patch-id: 8fc4f7595aac33a2164adb41c139dc3218be5bc6
> prerequisite-patch-id: 52bde56940b545c0e5f44d12811f9b9676bc311c
> prerequisite-patch-id: c0b93409e330d4b874b3702d67b57e2c4b0bde32
> prerequisite-patch-id: dbc6f65015852bbaf31e5f4efbee52c60bafb79f
> prerequisite-patch-id: d5c9bb074014a20938df8b55bb9088aa7b26d37b
> prerequisite-patch-id: d1ce44a3f9104aeead2c18d58a1470d1bd1ae531
>
> Best regards,
--
Regards,
Benjamin
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] media: i2c: vd55g1: fix VD55G0 streaming below 900 Mbps
2026-10-16 11:02 ` Benjamin Mugnier
@ 2026-10-16 14:55 ` George Neacsu
0 siblings, 0 replies; 3+ messages in thread
From: George Neacsu @ 2026-10-16 14:55 UTC (permalink / raw)
To: Benjamin Mugnier
Cc: Sylvain Petinot, Peter Marshall, Sakari Ailus,
Mauro Carvalho Chehab, fqwqf, Sergey Lebedev, linux-media,
linux-kernel
Hi Benjamin,
On 16/10/2026 12:02, Benjamin Mugnier wrote:
> We reworked the clock tree with Sergey so it may fix your issue too.
> Please test it once it hits the mailing list and we will make required
> adjustments.
Will do. When Sergey's driver is posted I will test it on the
Snapdragon Surface Pro 11 at 840 Mbps and report whether the longer
line is still needed there.
Thanks,
George
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2026-10-16 14:55 UTC | newest]
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2026-10-16 10:28 [PATCH v2] media: i2c: vd55g1: fix VD55G0 streaming below 900 Mbps George Neacsu via B4 Relay
2026-10-16 11:02 ` Benjamin Mugnier
2026-10-16 14:55 ` George Neacsu
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