Re: V4.1-RC build error after commit 77a3c6f

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

Hi Larry,

Thank you for the report.

On Saturday 11 July 2015 16:27:36 Larry Finger wrote:
> Beginning with the commit in the subject, I get the following build error:
> 
>    CC [M]  drivers/media/v4l2-core/videobuf2-core.o
> drivers/media/v4l2-core/videobuf2-core.c: In function
> ‘vb2_warn_zero_bytesused’: drivers/media/v4l2-core/videobuf2-core.c:1253:2:
> error: implicit declaration of function ‘__WARN’
> [-Werror=implicit-function-declaration]
>    __WARN();
>    ^
> cc1: some warnings being treated as errors
> 
> My .config is attached.

Indeed, __WARN isn't defined when CONFIG_BUG isn't set. My bad :-/

I've send a patch to fix this (you've been CC'ed), could you please review it 
?

And I've just noticed that I forgot to add your Reported-by: tag, please feel 
free to add it to the review.

> This problem has been bisected to the following commit:
> 
> commit 77a3c6fd90c94f635edb00d4a65f485687538791
> Author: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> Date:   Fri Jun 19 08:50:07 2015 -0300
> 
>      [media] vb2: Don't WARN when v4l2_buffer.bytesused is 0 for multiplanar
> buffers
> 
>      Commit f61bf13b6a07 ("[media] vb2: add allow_zero_bytesused flag to the
> vb2_queue struct") added a WARN_ONCE to catch usage of a deprecated API
> using a zero value for v4l2_buffer.bytesused.
> 
>      However, the condition is checked incorrectly, as the v4L2_buffer
>      bytesused field is supposed to be ignored for multiplanar buffers. This
> results in spurious warnings when using the multiplanar API.
> 
>      Fix it by checking v4l2_buffer.bytesused for uniplanar buffers and
>      v4l2_plane.bytesused for multiplanar buffers.
> 
>      Fixes: f61bf13b6a07 ("[media] vb2: add allow_zero_bytesused flag to the
> vb2_queue struct")
> 
>      Signed-off-by: Laurent Pinchart
> <laurent.pinchart+renesas@ideasonboard.com> Cc: stable@vger.kernel.org #
> for v4.0
>      Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
> 
> Thanks,
> 
> Larry

-- 
Regards,

Laurent Pinchart