On 4/20/19 8:15 AM, Damjan Jovanovic wrote:
> Recent changes to qcap/v4l.c resulted in the removal of mmap()
> for v4l2 devices, but read() is optional for device drivers and
> some don't support it. This isn't a major problem with the
> presense of libv4l2 though, as it can emulate read() on top of
> mmap(). However the code checks whether the device can read(),
> and if not, doesn't even try to use it, even though it can.
>
> Fix this by only warning that read() is being emulated, and
> continuing with libv4l2 if available.
>
> Also clarifies the logging.
>
> Signed-off-by: Damjan Jovanovic <damjan.jov@gmail.com>
> ---
>   dlls/qcap/v4l.c | 13 ++++++++-----
>   1 file changed, 8 insertions(+), 5 deletions(-)
>
>
>

This doesn't seem right; libv4l2 should massage the result of
VIDIOC_QUERYCAP to include V4L2_CAP_READWRITE. See
<https://git.linuxtv.org/v4l-utils.git/tree/lib/libv4l2/libv4l2.c#n1210>.