This patch fixes a race condition whereby a frame being captured may generate an
interrupt between requesting capture to halt and freeing buffers.
This condition is exposed by the earlier patch that explicitly calls
vb2_buffer_done() during stop streaming.
The solution is to wait for capture to finish prior to finalising these buffers.
Signed-off-by: Ian Molton <ian.mol...@codethink.co.uk>
Signed-off-by: William Towle <william.to...@codethink.co.uk>
---
drivers/media/platform/soc_camera/rcar_vin.c | 43 ++++++++++++++++++----------
1 file changed, 28 insertions(+), 15 deletions(-)
diff --git a/drivers/media/platform/soc_camera/rcar_vin.c
b/drivers/media/platform/soc_camera/rcar_vin.c
index 06ce705..aeda4e2 100644
--- a/drivers/media/platform/soc_camera/rcar_vin.c
+++ b/drivers/media/platform/soc_camera/rcar_vin.c
@@ -455,6 +455,29 @@ error:
vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
}
+/*
+ * Wait for capture to stop and all in-flight buffers to be finished with by
+ * the video hardware. This must be called under &priv->lock
+ *
+ */
+static void rcar_vin_wait_stop_streaming(struct rcar_vin_priv *priv)
+{
+ while (priv->state != STOPPED) {
+
+ /* issue stop if running */
+ if (priv->state == RUNNING)
+ rcar_vin_request_capture_stop(priv);
+
+ /* wait until capturing has been stopped */
+ if (priv->state == STOPPING) {
+ priv->request_to_stop = true;
+ spin_unlock_irq(&priv->lock);
+ wait_for_completion(&priv->capture_stop);
+ spin_lock_irq(&priv->lock);
+ }
+ }
+}
+
static void rcar_vin_videobuf_release(struct vb2_buffer *vb)
{
struct soc_camera_device *icd = soc_camera_from_vb2q(vb->vb2_queue);
@@ -462,7 +485,6 @@ static void rcar_vin_videobuf_release(struct vb2_buffer *vb)
struct rcar_vin_priv *priv = ici->priv;
unsigned int i;
int buf_in_use = 0;
-
spin_lock_irq(&priv->lock);
/* Is the buffer in use by the VIN hardware? */
@@ -474,20 +496,8 @@ static void rcar_vin_videobuf_release(struct vb2_buffer
*vb)
}
if (buf_in_use) {
- while (priv->state != STOPPED) {
-
- /* issue stop if running */
- if (priv->state == RUNNING)
- rcar_vin_request_capture_stop(priv);
-
- /* wait until capturing has been stopped */
- if (priv->state == STOPPING) {
- priv->request_to_stop = true;
- spin_unlock_irq(&priv->lock);
- wait_for_completion(&priv->capture_stop);
- spin_lock_irq(&priv->lock);
- }
- }
+ rcar_vin_wait_stop_streaming(priv);
+
/*
* Capturing has now stopped. The buffer we have been asked
* to release could be any of the current buffers in use, so
@@ -517,12 +527,15 @@ static void rcar_vin_stop_streaming(struct vb2_queue *vq)
spin_lock_irq(&priv->lock);
+ rcar_vin_wait_stop_streaming(priv);
+
for (i = 0; i < vq->num_buffers; ++i)
if (vq->bufs[i]->state == VB2_BUF_STATE_ACTIVE)
vb2_buffer_done(vq->bufs[i], VB2_BUF_STATE_ERROR);
list_for_each_safe(buf_head, tmp, &priv->capture)
list_del_init(buf_head);
+
spin_unlock_irq(&priv->lock);
}
--
1.9.1
--
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