uvc-gadget.git/lib, branch v0.2.0

slideshow-source: add slideshow source class

2022-12-06T14:42:12+00:00

The slideshow_source class is an implementation of the video_source
class that streams a set of images as video.

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

lib/jpg-source: Constrain fps

2022-11-30T13:48:26+00:00

As written the fps output by the jpg-source is unconstrained; it will
simply fill buffers as quickly as the USB subsysem can handle them.
This is not particularly realistic and also means that the frame rates
configured (and thus expected) by the host are not being adhered to.
Use the new timer infrastructure to slow down the buffer fill operation
such that the frame rates seen match those configured by the host.

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

lib/timer: Add timer infrastructure

2022-11-30T13:48:26+00:00

Some sources simply fill the buffers passed by the USB subsystem and
return them as quickly as possible. Particularly with compressed
formats operating at superspeed this rapidly results in unrealistic
frame rates.

Add infrastructure that allows us to define a specific
framerate and introduce blocking calls that constrain those sources
to the framerates expected by the host.

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

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