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authorMike Isely <isely@pobox.com>2009-09-23 18:06:57 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2009-11-07 12:55:10 -0200
commit1f95725755ab67f3198df3b5bf7517f926f310ca (patch)
tree9efac277e8c0db2e0a22e1716d1d58ab3ba0b578
parent78c948ab0cc44f9c8ae397d7d9d217bb498bfa2f (diff)
V4L/DVB (13230): s2255drv: Don't conditionalize video buffer completion on waiting processes
The s2255 driver had logic which aborted processing of a video frame if there was no process waiting on the video buffer in question. That simply doesn't work when the application is doing things in an asynchronous manner. If the application went to the trouble to queue the buffer in the first place, then the driver should always attempt to complete it - even if the application at that moment has its attention turned elsewhere. Applications which always blocked waiting for I/O on the capture device would not have been affected by this. Applications which *mostly* blocked waiting for I/O on the capture device probably only would have been somewhat affected (frame lossage, at a rate which goes up as the application blocks less). Applications which never blocked on the capture device (e.g. polling only) however would never have been able to receive any video frames, since in that case this "is anyone waiting on this?" check on the buffer never would have evalutated true. This patch just deletes that harmful check against the buffer's wait queue. Signed-off-by: Mike Isely <isely@pobox.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com> CC: stable@kernel.org
-rw-r--r--drivers/media/video/s2255drv.c5
1 files changed, 0 insertions, 5 deletions
diff --git a/drivers/media/video/s2255drv.c b/drivers/media/video/s2255drv.c
index 9e3262c0ba3..2c0bb06cab3 100644
--- a/drivers/media/video/s2255drv.c
+++ b/drivers/media/video/s2255drv.c
@@ -598,11 +598,6 @@ static int s2255_got_frame(struct s2255_dev *dev, int chn, int jpgsize)
buf = list_entry(dma_q->active.next,
struct s2255_buffer, vb.queue);
- if (!waitqueue_active(&buf->vb.done)) {
- /* no one active */
- rc = -1;
- goto unlock;
- }
list_del(&buf->vb.queue);
do_gettimeofday(&buf->vb.ts);
dprintk(100, "[%p/%d] wakeup\n", buf, buf->vb.i);