Re: [PATCH] [media] uvcvideo: Enable VIDIOC_CREATE_BUFS

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

Hi Hans,

On Friday 31 January 2014 09:43:00 Hans Verkuil wrote:
> I think you might want to add a check in uvc_queue_setup to verify the
> fmt that create_bufs passes. The spec says that: "Unsupported formats
> will result in an error". In this case I guess that the format basically
> should match the current selected format.
> 
> I'm unhappy with the current implementations of create_bufs (see also this
> patch:
> http://www.mail-archive.com/linux-media@vger.kernel.org/msg70796.html).
> 
> Nobody is actually checking the format today, which isn't good.
> 
> The fact that the spec says that the fmt field isn't changed by the driver
> isn't helping as it invalidated my patch from above, although that can be
> fixed.
> 
> I need to think about this some more, but for this particular case you can
> just do a memcmp of the v4l2_pix_format against the currently selected
> format and return an error if they differ. Unless you want to support
> different buffer sizes as well?

Isn't the whole point of VIDIOC_CREATE_BUFS being able to create buffers of 
different resolutions than the current active resolution ?

-- 
Regards,

Laurent Pinchart