On 4/20/19 11:55 AM, Damjan Jovanovic wrote:
>
>
> On Sat, Apr 20, 2019 at 6:07 PM Zebediah Figura <z.figura12@gmail.com
> <mailto:z.figura12@gmail.com>> wrote:
>
> On 4/20/19 10:56 AM, Damjan Jovanovic wrote:
> >
> >
> > On Sat, Apr 20, 2019 at 5:44 PM Zebediah Figura
> <z.figura12@gmail.com <mailto:z.figura12@gmail.com>
> > <mailto:z.figura12@gmail.com <mailto:z.figura12@gmail.com>>> wrote:
> >
> > On 4/20/19 10:31 AM, Damjan Jovanovic wrote:
> > >
> > >
> > > On Sat, Apr 20, 2019 at 4:52 PM Zebediah Figura
> > <z.figura12@gmail.com <mailto:z.figura12@gmail.com>
> <mailto:z.figura12@gmail.com <mailto:z.figura12@gmail.com>>
> > > <mailto:z.figura12@gmail.com <mailto:z.figura12@gmail.com>
> <mailto:z.figura12@gmail.com <mailto:z.figura12@gmail.com>>>> wrote:
> > >
> > > 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 <mailto:damjan.jov@gmail.com>
> > <mailto:damjan.jov@gmail.com <mailto:damjan.jov@gmail.com>>
> > > <mailto:damjan.jov@gmail.com
> <mailto:damjan.jov@gmail.com> <mailto:damjan.jov@gmail.com
> <mailto: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>.
> > >
> > >
> > > On FreeBSD 11.2 with libv4l-1.6.3_4, that is certainly NOT the
> > case. It
> > > could be a newer or not yet released feature.
> > >
> > >
> > >
> >
> > It's been the case since libv4l2 0.5:
> >
> <https://git.linuxtv.org/v4l-utils.git/commit/lib/libv4l2/libv4l2.c?id=0215f2ac08c3ad0dc66ad8036f4e186a5e8f56d6>
> >
> > If FreeBSD is using 1.6.3, then I think something else is
> wrong. Are
> > you
> > sure that libv4l2 is actually being loaded?
> >
> >
> > int v4l2_ioctl(int fd, unsigned long int request, ...)
> > {
> > ...
> > if (devices[index].convert == NULL)
> > goto no_capture_request;
> >
> > <your code nippet from above>
> >
> > no_capture_request:
> >
> >
> >
> > So the code that would set that flag, is skipped if the .convert
> field
> > is NULL.
> >
> > When is it NULL?
> >
> >
> >
>
> If my reading of the code is correct, only when v4l2_fd_open() is
> called
> manually with V4L2_DISABLE_CONVERSION. Obviously we don't do that.
>
> Perhaps setting LIBV4L2_LOG_FILENAME might give some hints as to what's
> going wrong?
>
>
>
> int v4l2_fd_open(int fd, int v4l2_flags)
> {
> ...
> <The actual ioctl() returns cap.capabilities = 0x84a00001,
> cap.device_caps = 0x04a00000>
>
> if (cap.capabilities & V4L2_CAP_DEVICE_CAPS)
> cap.capabilities = cap.device_caps;
> if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE) ||
> !(cap.capabilities & (V4L2_CAP_STREAMING |
> V4L2_CAP_READWRITE))) {
> goto no_capture;
> }
>
> 0x000000001 = V4L2_CAP_VIDEO_CAPTURE
> 0x00200000 = V4L2_CAP_EXT_PIX_FORMAT
> 0x00800000 = V4L2_CAP_META_CAPTURE
> 0x040000000 = V4L2_CAP_STREAMING
> 0x800000000 = V4L2_CAP_DEVICE_CAPS
>
> So cap.capabilities have all those flags set, but cap.device_caps lacks
> V4L2_CAP_VIDEO_CAPTURE.
> cap.capabilities is overwritten by cap.device_caps, thus
> V4L2_CAP_VIDEO_CAPTURE is cleared.
> Since libv4l2 only manages devices with V4L2_CAP_VIDEO_CAPTURE set, and
> that flag is now missing, the first condition in the next "if" takes the
> goto, and .convert remains NULL.
> With .convert NULL, libv4l2 no longer manages the device, so
> communication is directly between Wine and kernel.
> Therefore the V4L2_CAP_READWRITE flag is not going to be set in
> v4l2_ioctl(), and libv4l2 cannot be made to do any conversions for us.
> But then again we can't use a device without V4L2_CAP_VIDEO_CAPTURE
> either, libv4l2 or not.
>
> I think the fundamental problem is that Wine is trying to use
> /dev/video1 which is broken, due to a bug in devenum that overwrites the
> working /dev/video0 registry entry with it, because their descriptions
> are the same.
>
>
>
Thanks, I've just sent patches to resolve both of these bugs.