v4l2: v4l2_camera_proxy: Don't return -EINVAL for zero sizeimage in REQBUFS

If VIDIOC_REQBUFS returns -EINVAL, it signals to the application that
the requested buffer or memory type is not supported. If we return
-EINVAL due to a zero sizeimage, then the application will think that we
don't support a memory type that we actually do. We cannot error on a
zero sizeimage, because reqbufs could be called merely to probe what IO
methods we support; qv4l2, for example, called reqbufs once with userptr
and once more with mmap, both times with count=1.

On the other hand, sizeimage will be zero for formats whose size we
don't know how to calculate, such as MJPEG. If we try to stream such
formats anyway, we will get a floating point exception and crash. Issue
a warning for now, and don't return -EINVAL, so that we can continue
operation.

Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

0 files changed, 0 insertions, 0 deletions