Re: [PATCH] media: bcm2835-unicam: Fix pipeline wrong validation for unpacked formats

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Thu, Jul 16, 2026 at 10:22:03AM +0300, Eugen Hristev wrote:
> On 6/3/26 09:48, Jai Luthra wrote:
> > Quoting Eugen Hristev (2026-05-20 21:07:00)
> >> The commit
> >> 08f9794d9b79 ("media: bcm2835-unicam: Fix RGB format / mbus code association")
> >> introduced a check to see whether the format requested is the same as the
> >> fourcc in the format list.
> >>
> >> However, this breaks the case when userspace requested an unpacked fourcc,
> >> e.g. RG10.
> >>
> >> Unicam can work with or without unpacking pixels, e.g. pRAA or RG10, depending
> >> on what userspace requests.
> >> In the unpacking case, a dedicated register is being set.
> >>
> >> If the userspace requests pRAA, this works, because the check validates the
> >> pipeline:
> >>
> >> v4l2-ctl -d /dev/video0 --set-fmt-video=width=3280,height=2464,pixelformat=pRAA \
> >>  --stream-mmap --stream-count=1 --stream-to=frame.raw
> >>
> >> but, with
> >> v4l2-ctl -d /dev/video0 --set-fmt-video=width=3280,height=2464,pixelformat=RG10 \
> >> --stream-mmap --stream-count=1 --stream-to=frame.raw
> >>
> >> unicam complains at validation level:
> >>
> >> image: format mismatch: 0x300f <=> RG10 little-endian (0x30314752)
> >>
> >> This should work, because MEDIA_BUS_FMT_SRGGB10_1X10 can be packed into either
> >> RG10 or pRAA depending on the packing register.
> >>
> >> To fix this, modified the condition check to also allow in the case when
> >> requested format (fmt->pixelformat) is equal to fmtinfo->unpacked_fourcc.
> >>
> >> Fixes: 08f9794d9b79 ("media: bcm2835-unicam: Fix RGB format / mbus code association")
> >> Signed-off-by: Eugen Hristev <ehristev@kernel.org>
> >> ---
> >>  drivers/media/platform/broadcom/bcm2835-unicam.c | 3 ++-
> >>  1 file changed, 2 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/media/platform/broadcom/bcm2835-unicam.c b/drivers/media/platform/broadcom/bcm2835-unicam.c
> >> index 8d28ba0b59a3..cc7627e9a51a 100644
> >> --- a/drivers/media/platform/broadcom/bcm2835-unicam.c
> >> +++ b/drivers/media/platform/broadcom/bcm2835-unicam.c
> >> @@ -2158,7 +2158,8 @@ static int unicam_video_link_validate(struct media_link *link)
> >>                  * In order to allow the applications using the old behaviour to
> >>                  * run, let's accept the old combination, but warn about it.
> >>                  */
> >> -               if (fmtinfo->fourcc != fmt->pixelformat) {
> >> +               if (fmt->pixelformat != fmtinfo->fourcc &&
> >> +                   fmt->pixelformat != fmtinfo->unpacked_fourcc) {
> >>                         if ((fmt->pixelformat == V4L2_PIX_FMT_BGR24 &&
> >>                              format->code == MEDIA_BUS_FMT_BGR888_1X24) ||
> >>                             (fmt->pixelformat == V4L2_PIX_FMT_RGB24 &&
> >>
> > 
> > Reviewed-by: Jai Luthra <jai.luthra@ideasonboard.com>
> > 
> 
> Hi Sakari,
> 
> I saw you taking some of the patches on unicam, this one is the most
> important as all unpacked formats are basically broken for a very long
> time (months) and the patch is pending for quite some time.
> 
> This should also go in stable as some older versions also affected.

The commit message should include

Cc: stable@vger.kernel.org

after the Fixes: tag. Sakari can likely add that when applying.

> >> ---
> >> base-commit: e98d21c170b01ddef366f023bbfcf6b31509fa83
> >> change-id: 20260520-bcmpi-2c4850314e21

-- 
Regards,

Laurent Pinchart