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Commit e0fadfd3 authored by Aidan Thornton's avatar Aidan Thornton Committed by Mauro Carvalho Chehab
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V4L/DVB (7548): Various fixes for the em28xx videobuf code 



- Aborting buffer_filled if no-one's waiting on the waitqueue probably isn't
  what we want, since just because no-one's waiting for it now doesn't mean they
  wouldn't dequeue it in time. (vivi gets away with this, possibly because it
  can fill each buffer much faster.)

- The first BUG_ON(lencopy <= 0); really isn't worth causing a kernel panic
  over, especially since there are some reasons why it could trigger in normal use.

- The top and botom frames are actually the wrong way around.

Signed-off-by: default avatarAidan Thornton <makosoft@googlemail.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@infradead.org>
parent e74153d4

drivers/media/video/em28xx/em28xx-video.c

+7 −13
Original line number Diff line number Diff line
@@ -135,14 +135,6 @@ static inline void buffer_filled(struct em28xx *dev, 
{

	mod_timer(&dma_q->timeout, jiffies+BUFFER_TIMEOUT);



	/* Nobody is waiting something to be done, just return */

	if (!waitqueue_active(&buf->vb.done)) {

		printk(KERN_ERR "em28xx: buffer underrun at %ld\n",

				jiffies);



		return;

	}



	/* Advice that buffer was filled */

	em28xx_isocdbg("[%p/%d] wakeup\n", buf, buf->vb.i);

	buf->vb.state = VIDEOBUF_DONE;
@@ -202,7 +194,8 @@ static void em28xx_copy_video(struct em28xx *dev, 
			       ((char *)outp + buf->vb.size));

		lencopy = remain = (char *)outp + buf->vb.size - (char *)startwrite;

	}

	BUG_ON(lencopy <= 0);

	if (lencopy <= 0)

		return;

	memcpy(startwrite, startread, lencopy);



	remain -= lencopy;
@@ -356,11 +349,13 @@ static inline int em28xx_isoc_copy(struct urb *urb) 
		if (p[0] == 0x22 && p[1] == 0x5a) {

			/* FIXME - are the fields the right way around? */

			em28xx_isocdbg("Video frame, length=%i, %s\n", len,

					(p[2] & 1)? "top" : "bottom");

					(p[2] & 1)? "odd" : "even");

			em28xx_isocdbg("Current buffer is: outp = 0x%p,"

				       " len = %i\n", outp, (int)buf->vb.size);



			if (p[2] & 1) {

			if (p[2] & 1)

				buf->top_field = 0;

			else {

				if (buf->receiving) {

					buffer_filled(dev, dma_q, buf);

					rc = get_next_buf(dma_q, &buf);
@@ -371,8 +366,7 @@ static inline int em28xx_isoc_copy(struct urb *urb) 
				}



				buf->top_field = 1;

			} else

				buf->top_field = 0;

			}

			buf->receiving = 1;

			dma_q->pos = 0;

		} else if (p[0] == 0x33 && p[1] == 0x95 && p[2] == 0x00) {