uvc-gadget.git/lib, branch v0.1.0

lib: uvc: Respond to control requests with dummy values

2022-11-22T16:08:30+00:00

Without a response, the host will assume there has been an error and
throw a bunch of errors. The noise of those errors makes it difficult
to see what's going on properly, so return a dummy response that
silences the errors until the functionality is properly implemented.

Reviewed-by: Kieran Bingham 
Signed-off-by: Daniel Scally 
Signed-off-by: Kieran Bingham

lib: uvc: Add control names in output prints

2022-11-22T16:08:30+00:00

It's easier to see what's going on at a glance when the output is
human-readable, so replace the control codes with their names.

Reviewed-by: Kieran Bingham 
Signed-off-by: Daniel Scally 
Signed-off-by: Kieran Bingham

lib: uvc: Drop maxsize

2022-11-22T16:08:24+00:00

The maxsize field of struct uvc_device is probably unecessary even if
it weren't currently fixed at 0. It's used to set dwMaxVideoFrameSize
in addition to the sizeimage member of a struct v4l2_pix_fmt (multiplied
in the latter instance by 1.5x). The documentary definitions for those
two values are such that they should be identical though, so simply
set dwMaxVideoFrameSize to width*height*2 (to maintain commonality
with other UVC Video devices) and use that to set the sizeimage.

Reviewed-by: Kieran Bingham 
Signed-off-by: Daniel Scally 
Signed-off-by: Kieran Bingham

lib: events: Use list_for_each_entry() instead of the _safe() version

2022-11-22T16:07:58+00:00

For the UVC_EVENT_STREAMOFF event, the callback frees _other_ events
because it's closing down the pipe. The use of the _safe() version
of the list iterator results in a use-after-free of those events
because they're fetched before the callback that frees them. The
_safe() version is unecessary here; no other callback's behaviour
requires it.

Reviewed-by: Kieran Bingham 
Signed-off-by: Daniel Scally 
Signed-off-by: Kieran Bingham

jpg-source: add jpg source class

2022-11-22T16:05:21+00:00

The jpg_source class is an implementation of the video_source class that
streams a still jpg image as video.

Reviewed-by: Kieran Bingham 
Signed-off-by: Paul Elder 
Signed-off-by: Daniel Scally 
Signed-off-by: Kieran Bingham

test-source: add test source class

2022-11-22T16:02:25+00:00

The test_source class is an implementation of the video_source class
that generates a test pattern in userspace to provide video. We have
some operations which are implemented as no-ops. To quiet the
compiler warnings this causes, flag their arguments as unused.

Reviewed-by: Kieran Bingham 
Signed-off-by: Paul Elder 
Signed-off-by: Daniel Scally 
Signed-off-by: Kieran Bingham

v4l2: write size value when dequeueing buffer

2022-11-22T16:02:25+00:00

When we dequeue a buffer from a V4L2 device, it would be good to know
the size of the buffer. Save it to our struct video_buffer when
dequeueing.

Reviewed-by: Daniel Scally 
Reviewed-by: Kieran Bingham 
Signed-off-by: Paul Elder 
Signed-off-by: Kieran Bingham

v4l2: populate video_buffer mem field at dequeue

2022-11-22T16:02:25+00:00

Our v4l2_queue_buffer and v4l2_dequeue_buffer functions give us a
wrapper around the raw V4L2 ioctls with a wrapper struct video_buffer
around the raw struct v4l2_buffer. The problem is that the
video_buffer's mem field is never populated, so there's no way to access
the mem that the buffer refers to given only the buffer.

Populate the video_buffer's mem field at v4l2_dequeue_buffer based on
the dequeued v4l2 buf's index.

Reviewed-by: Daniel Scally 
Reviewed-by: Kieran Bingham 
Signed-off-by: Paul Elder 
Signed-off-by: Kieran Bingham

stream: allow buffers to be allocated on uvc side

2022-11-22T16:02:25+00:00

We want to allow video sources whose data is generated in userspace.
Currently buffers are allocated on the V4L2-backed video source and
exported to the uvc-gadget's V4L2 device. Since a video source with
data generated in userspace will not be backed by a V4L2 device, we
allow a way for buffers to be allocated on uvc-gadget's V4L2 device.

As a corollary, the way the buffers are passed has to be changed as
well. Previously they were queued and dequeued between the V4L2 video
source and uvc and vice versa. To allow a video source not backed by
a V4L2 device, we allow an alternative flow where they are dequeued and
queued from and to uvc, and giving a chance to the video source to fill
the buffer in between.

Reviewed-by: Daniel Scally 
Reviewed-by: Kieran Bingham 
Signed-off-by: Paul Elder 
Signed-off-by: Kieran Bingham

video-source: add fill_buffer

2022-11-22T16:02:25+00:00

We are preparing to allow video sources whose data is generated in
userspace. To this end, add a fill_buffer function to video_source.

Reviewed-by: Daniel Scally 
Reviewed-by: Kieran Bingham 
Signed-off-by: Paul Elder 
Signed-off-by: Kieran Bingham