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authorGuennadi Liakhovetski <g.liakhovetski@gmx.de>2009-08-25 11:46:51 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2009-09-19 00:18:51 -0300
commitcca0e54905259a456d97652d4f1e2fe8b188b6ad (patch)
tree82a0af7fadc341e4955628f45c2110439c9701e8 /drivers/media/video
parentfa48984e36ee73e964eeb994a45de6525114e871 (diff)
V4L/DVB (12520): sh-mobile-ceu-camera: do not wait for interrupt when releasing buffers
Patch [PATCH] video: use videobuf_waiton() in sh_mobile_ceu free_buffer() was not quite correct. It closed a race, but introduced a potential lock-up, if for some reason an interrupt does not come. This has been observed in tests with tw9910. This patch safely dequeues buffers without waiting for their completion. It also moves a buffer state assignment under a spinlock to make it atomic with queuing of the buffer. Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/video')
-rw-r--r--drivers/media/video/sh_mobile_ceu_camera.c27
1 files changed, 27 insertions, 0 deletions
diff --git a/drivers/media/video/sh_mobile_ceu_camera.c b/drivers/media/video/sh_mobile_ceu_camera.c
index 4c4b60c3226..c0dc4a1e8e5 100644
--- a/drivers/media/video/sh_mobile_ceu_camera.c
+++ b/drivers/media/video/sh_mobile_ceu_camera.c
@@ -307,6 +307,27 @@ static void sh_mobile_ceu_videobuf_queue(struct videobuf_queue *vq,
static void sh_mobile_ceu_videobuf_release(struct videobuf_queue *vq,
struct videobuf_buffer *vb)
{
+ struct soc_camera_device *icd = vq->priv_data;
+ struct soc_camera_host *ici = to_soc_camera_host(icd->dev.parent);
+ struct sh_mobile_ceu_dev *pcdev = ici->priv;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pcdev->lock, flags);
+
+ if (pcdev->active == vb) {
+ /* disable capture (release DMA buffer), reset */
+ ceu_write(pcdev, CAPSR, 1 << 16);
+ pcdev->active = NULL;
+ }
+
+ if ((vb->state == VIDEOBUF_ACTIVE || vb->state == VIDEOBUF_QUEUED) &&
+ !list_empty(&vb->queue)) {
+ vb->state = VIDEOBUF_ERROR;
+ list_del_init(&vb->queue);
+ }
+
+ spin_unlock_irqrestore(&pcdev->lock, flags);
+
free_buffer(vq, container_of(vb, struct sh_mobile_ceu_buffer, vb));
}
@@ -326,6 +347,10 @@ static irqreturn_t sh_mobile_ceu_irq(int irq, void *data)
spin_lock_irqsave(&pcdev->lock, flags);
vb = pcdev->active;
+ if (!vb)
+ /* Stale interrupt from a released buffer */
+ goto out;
+
list_del_init(&vb->queue);
if (!list_empty(&pcdev->capture))
@@ -340,6 +365,8 @@ static irqreturn_t sh_mobile_ceu_irq(int irq, void *data)
do_gettimeofday(&vb->ts);
vb->field_count++;
wake_up(&vb->done);
+
+out:
spin_unlock_irqrestore(&pcdev->lock, flags);
return IRQ_HANDLED;