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Commit cca0e549 authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Mauro Carvalho Chehab
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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: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent fa48984e

drivers/media/video/sh_mobile_ceu_camera.c

+27 −0
Original line number Diff line number Diff line
@@ -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;