[PATCH v2] clients: teach simple-dmabuf-v4l to deal with flipped input

[Derek Foreman]

On 07/02/17 07:17 PM, Bryce Harrington wrote:
> On Tue, Feb 07, 2017 at 11:48:47AM +0200, Pekka Paalanen wrote:
>> On Mon,  6 Feb 2017 12:57:41 -0500
>> Micah Fedke <micah.fedke at collabora.co.uk> wrote:
>>
>>> The v4l2 API can be queried to detect if the input video image is
>>> horizontally or vertically flipped. If the image is y-flipped, we can
>>> set the ZWP_LINUX_BUFFER_PARAMS_V1_FLAGS_Y_INVERT flag to notify the
>>> compositor.  If the image is h-flipped, we can only print a warning
>>> since linux_buffer_params_v1 does not support horizontal flipping.
>>>
>>> Signed-off-by: Micah Fedke <micah.fedke at collabora.co.uk>
>>> ---
>>> This version addresses Pekka's comments by renaming check_v4l2_control to
>>> check_v4l2_control_bool, removing the len parameter, separating out the logic
>>> tests in check_v4l2_control_bool and fixing spacing issues.
>>>
>>>  clients/simple-dmabuf-v4l.c | 62 +++++++++++++++++++++++++++++++++++++++------
>>>  1 file changed, 54 insertions(+), 8 deletions(-)
>>
>> Hi,
>>
>> looks fine, pushed with my R-b:
>>    9a200d7..0fee977  master -> master
>
> Breaks the build on older linux kernels.
>
>   CC       clients/weston_simple_dmabuf_v4l-simple-dmabuf-v4l.o
> clients/simple-dmabuf-v4l.c:358:25: warning: ‘struct v4l2_query_ext_ctrl’ declared inside parameter list [enabled by default]
>                          const int expected_value)
>                          ^
> clients/simple-dmabuf-v4l.c:358:25: warning: its scope is only this definition or declaration, which is probably not what you want [enabled by default]
> clients/simple-dmabuf-v4l.c: In function ‘check_v4l2_control_bool’:
> clients/simple-dmabuf-v4l.c:363:18: error: dereferencing pointer to incomplete type
>   ctrl.id = qectrl->id;
>                   ^
> et al.
>
> Builds ok with the patch reverted, or with --disable-simple-dmabuf-v4l-client set.

Ouch, bad timing for a build break.

IMHO this patch should land before the final release, to get all the 
y-inversion fix-ups in at the same time, but I don't like the idea of a 
beta release that fails to build after it succeeds at configure for some 
folk...

If a quick fix isn't coming, maybe revert it before the beta release?

It's not a huge stretch to consider properly dealing with y-flip a bug 
fix, and it is just a test app, so I think it'd be ok to land it during 
the beta...