Re: [PATCH v3 00/29] Rework frame descriptors

[Mattijs Korpershoek <mkorpershoek@kernel.org>]

Hi Sakari,

Thank you for the series.

On Mon, Aug 24, 2026 at 15:14, Sakari Ailus <sakari.ailus@linux.intel.com> wrote:

> Hi folks,
>
> This smallish set makes frame descriptors dynamically allocated and
> implements a single-entry frame descriptor based on the device's format,
> using a new helper called v4l2_subdev_get_frame_desc(). All drivers that
> do not obtain their frame descriptor from upstream are converted. The
> helper also obtains a frame descriptor for the desired type (parallel or
> CSI-2) and checks there's at least one entry there. These checks are
> removed from drivers that currently perform them. (Some drivers also check
> there's exactly a single frame descriptor entry but I think in most cases
> this check could be loosened. That could be done after this set.)
>
> More formats can be added to df-to-mbus conversion as needed. These are
> meant to be initial formats that are enough for typical raw sensors (and
> one RGB format, too).
>
> In the long run this information should probably reside in sub-device
> state. This set however avoids having all receiver drivers to work with
> sub-device drivers (~ 100 of such exist) that have a single stream and so
> do not implement get_frame_desc() op.

With this series, I could sucessfully run a capture using a TI AM69-SK
with the Arducam FPD V3Link[1] using the following device tree overlays:
    ti/k3-am68-sk-v3link-fusion.dtbo ti/k3-v3link-imx219-0-0.dtbo

(See TI's doc [2] for the device tree overlays)

root@am69-sk:~# yavta --capture=10 --file='capture-#-srggb8.bin' --size 1920x1080 --format SRGGB8 /dev/video4
Device /dev/video4 opened.
Device `j721e-csi2rx' on `platform:4500000.ticsi2rx' (driver 'j721e-csi2rx') supports video, capture, without mplanes.
Video format set: SRGGB8 (42474752) 1920x1080 (stride 1920) field none buffer size 2073600
Video format: SRGGB8 (42474752) 1920x1080 (stride 1920) field none buffer size 2073600
8 buffers requested.
length: 2073600 offset: 0 timestamp type/source: mono/EoF
Buffer 0/0 mapped at address 0xffff86a55000.
length: 2073600 offset: 32768 timestamp type/source: mono/EoF
Buffer 1/0 mapped at address 0xffff8685a000.
length: 2073600 offset: 65536 timestamp type/source: mono/EoF
Buffer 2/0 mapped at address 0xffff8665f000.
length: 2073600 offset: 98304 timestamp type/source: mono/EoF
Buffer 3/0 mapped at address 0xffff86464000.
length: 2073600 offset: 131072 timestamp type/source: mono/EoF
Buffer 4/0 mapped at address 0xffff86269000.
length: 2073600 offset: 163840 timestamp type/source: mono/EoF
Buffer 5/0 mapped at address 0xffff8606e000.
length: 2073600 offset: 196608 timestamp type/source: mono/EoF
Buffer 6/0 mapped at address 0xffff85e73000.
length: 2073600 offset: 229376 timestamp type/source: mono/EoF
Buffer 7/0 mapped at address 0xffff85c78000.
0 (0) [-] any 0 2073600 B 105.308050 105.308081 11.612 fps ts mono/EoF
1 (1) [-] any 1 2073600 B 105.341380 105.341435 30.003 fps ts mono/EoF
2 (2) [-] any 2 2073600 B 105.374708 105.374764 30.005 fps ts mono/EoF
3 (3) [-] any 3 2073600 B 105.408031 105.408079 30.009 fps ts mono/EoF
4 (4) [-] any 4 2073600 B 105.441357 105.441394 30.007 fps ts mono/EoF
5 (5) [-] any 5 2073600 B 105.474683 105.474721 30.007 fps ts mono/EoF
6 (6) [-] any 6 2073600 B 105.508009 105.508037 30.007 fps ts mono/EoF
7 (7) [-] any 7 2073600 B 105.541334 105.541368 30.008 fps ts mono/EoF
8 (0) [-] any 8 2073600 B 105.574664 105.574707 30.003 fps ts mono/EoF
9 (1) [-] any 9 2073600 B 105.607990 105.608044 30.007 fps ts mono/EoF
Captured 10 frames in 0.386114 seconds (25.899081 fps, 53704334.562154 B/s).
8 buffers released.

Base: commit 56c29fa3ee66 ("media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement")

Tested-by: Mattijs Korpershoek <mkorpershoek@kernel.org> # am69-sk

[1] https://www.arducam.com/arducam-v3link-camera-kit-for-ti-development-boards.html
[2] https://software-dl.ti.com/jacinto7/esd/processor-sdk-linux-am69/11_00_10_01/exports/docs/linux/Foundational_Components/Kernel/Kernel_Drivers/Camera/CSI2RX.html