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 <[email protected]> --- diff --git a/drivers/media/video/sh_mobile_ceu_camera.c b/drivers/media/video/sh_mobile_ceu_camera.c index d890f8d..67c7dcd 100644 --- a/drivers/media/video/sh_mobile_ceu_camera.c +++ b/drivers/media/video/sh_mobile_ceu_camera.c @@ -296,8 +306,8 @@ static void sh_mobile_ceu_videobuf_queue(struct videobuf_queue *vq, dev_dbg(&icd->dev, "%s (vb=0x%p) 0x%08lx %zd\n", __func__, vb, vb->baddr, vb->bsize); - vb->state = VIDEOBUF_QUEUED; spin_lock_irqsave(&pcdev->lock, flags); + vb->state = VIDEOBUF_QUEUED; list_add_tail(&vb->queue, &pcdev->capture); if (!pcdev->active) { @@ -311,6 +321,27 @@ 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)); } @@ -330,6 +361,10 @@ 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)) @@ -344,6 +379,8 @@ 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; -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
