Commit 296da3cd authored Oct 09, 2011 by Hans de Goede Committed by Mauro Carvalho Chehab Mar 27, 2012

[media] pwc: poll(): Check that the device has not beem claimed for streaming already



Some apps which use read() start the streaming through a call to poll(),
this means that if another app has already claimed the device for streaming
(through for example a s_fmt, or a reqbufs), that the poll should fail instead
of getting passed through to vb2_poll.

We only check for this when the app is polling for reads, so that ctrl events
still work.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

parent 0bf0f713

drivers/media/video/pwc/pwc-if.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -625,10 +625,19 @@ static ssize_t pwc_video_read(struct file file, char __user buf,
		static unsigned int pwc_video_poll(struct file file, poll_table wait)
		{
		struct pwc_device *pdev = video_drvdata(file);
		unsigned long req_events = poll_requested_events(wait);

		if (!pdev->udev)
		return POLL_ERR;

		if ((req_events & (POLLIN \| POLLRDNORM)) &&
		pdev->vb_queue.num_buffers == 0 &&
		!pdev->iso_init) {
		/* This poll will start a read stream, check capt_file */
		if (pwc_test_n_set_capt_file(pdev, file))
		return POLL_ERR;
		}

		return vb2_poll(&pdev->vb_queue, file, wait);
		}