Multiple V4L2 formats can be associated with a single PixelFormat.
Now that users of V4L2PixelFormat::fromPixelFormat() have been converted
to use V4L2VideoDevice::toV4L2PixelFormat(), return the full list of
V4L2 formats in order to prepare to match them against the ones
supported by the video device.
The V4L2 compatibility layer, not having any video device to interact
with, is converted to use the first returned format unconditionally.
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Paul Elder <paul.elder@ideasonboard.com>
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