Drivers are now required to implement the stop_streaming() callback
to ensure that all ongoing hardware operations are finished and their
ownership of buffers is ceded.
Drivers do not have to call vb2_buffer_done() for each buffer they own
anymore.
Also remove the return value from the callback.
Signed-off-by: Pawel Osciak <pawel@xxxxxxxxxx>
---
drivers/media/video/videobuf2-core.c | 16 ++++++++++++++--
include/media/videobuf2-core.h | 16 +++++++---------
2 files changed, 21 insertions(+), 11 deletions(-)
diff --git a/drivers/media/video/videobuf2-core.c b/drivers/media/video/videobuf2-core.c
index 6e69584..59d5e8b 100644
--- a/drivers/media/video/videobuf2-core.c
+++ b/drivers/media/video/videobuf2-core.c
@@ -640,6 +640,9 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
struct vb2_queue *q = vb->vb2_queue;
unsigned long flags;
+ if (atomic_read(&q->queued_count) == 0)
+ return;
+
if (vb->state != VB2_BUF_STATE_ACTIVE)
return;
@@ -1178,12 +1181,20 @@ static void __vb2_queue_cancel(struct vb2_queue *q)
unsigned int i;
/*
- * Tell driver to stop all transactions and release all queued
+ * Tell the driver to stop all transactions and release all queued
* buffers.
*/
if (q->streaming)
call_qop(q, stop_streaming, q);
+
+ /*
+ * All buffers should now not be in use by the driver anymore, but we
+ * have to manually set queued_count to 0, as the driver was not
+ * required to call vb2_buffer_done() from stop_streaming() for all
+ * buffers it had queued.
+ */
q->streaming = 0;
+ atomic_set(&q->queued_count, 0);
/*
* Remove all buffers from videobuf's list...
@@ -1197,7 +1208,7 @@ static void __vb2_queue_cancel(struct vb2_queue *q)
wake_up_all(&q->done_wq);
/*
- * Reinitialize all buffers for next use.
+ * Reinitialize all buffers for future use.
*/
for (i = 0; i < q->num_buffers; ++i)
q->bufs[i]->state = VB2_BUF_STATE_DEQUEUED;
@@ -1440,6 +1451,7 @@ int vb2_queue_init(struct vb2_queue *q)
BUG_ON(!q->ops->queue_setup);
BUG_ON(!q->ops->buf_queue);
+ BUG_ON(!q->ops->stop_streaming);
INIT_LIST_HEAD(&q->queued_list);
INIT_LIST_HEAD(&q->done_list);
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index f3bdbb2..8115fe9 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -184,7 +184,7 @@ struct vb2_buffer {
/**
* struct vb2_ops - driver-specific callbacks to be implemented by the driver
- * Required: queue_setup, buf_queue. The rest is optional.
+ * Required: queue_setup, buf_queue, stop_streaming. The rest is optional.
*
* @queue_setup: used to negotiate queue parameters between the userspace
* and the driver; called before memory allocation;
@@ -231,13 +231,11 @@ struct vb2_buffer {
* the driver before streaming begins (such as enabling
* the device);
* @stop_streaming: called when the 'streaming' state must be disabled;
- * drivers should stop any DMA transactions here (or wait
- * until they are finished) and give back all the buffers
- * received via buf_queue() by calling vb2_buffer_done()
- * for each of them;
- * drivers can use the vb2_wait_for_all_buffers() function
- * here to wait for asynchronous completion events that
- * call vb2_buffer_done(), such as ISRs;
+ * drivers should stop any DMA transactions here (or wait
+ * until they are finished) before returning;
+ * drivers can use the vb2_wait_for_all_buffers() function
+ * here to wait for asynchronous completion events, such
+ * as ISRs;
* @buf_queue: passes a buffer to the driver; the driver may start
* a hardware operation on that buffer; this callback
* MUST return immediately, i.e. it may NOT wait for
@@ -259,7 +257,7 @@ struct vb2_ops {
void (*buf_cleanup)(struct vb2_buffer *vb);
int (*start_streaming)(struct vb2_queue *q);
- int (*stop_streaming)(struct vb2_queue *q);
+ void (*stop_streaming)(struct vb2_queue *q);
void (*buf_queue)(struct vb2_buffer *vb);
};
--
1.7.4.2
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