From 1f95725755ab67f3198df3b5bf7517f926f310ca Mon Sep 17 00:00:00 2001 From: Mike Isely Date: Wed, 23 Sep 2009 18:06:57 -0300 Subject: [PATCH] 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 Signed-off-by: Mauro Carvalho Chehab CC: stable@kernel.org --- drivers/media/video/s2255drv.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/drivers/media/video/s2255drv.c b/drivers/media/video/s2255drv.c index 9e3262c0ba37..2c0bb06cab3b 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); -- 2.39.5