Hi,
On Thu, Sep 07, 2017 at 03:42:21PM -0300, Gustavo Padovan wrote:
From: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>
For explicit synchronization (and soon for HAL3/Request API) we need
the v4l2-driver to guarantee the ordering in which the buffers were queued
by userspace. This is already true for many drivers, but we never needed
to say it.
Signed-off-by: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>
---
include/media/videobuf2-core.h | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 5ed8d3402474..20099dc22f26 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -508,6 +508,9 @@ struct vb2_buf_ops {
* @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the
* last decoded buffer was already dequeued. Set for capture queues
* when a buffer with the V4L2_BUF_FLAG_LAST is dequeued.
+ * @ordered: if the driver can guarantee that the queue will be ordered or not.
+ * The default is not ordered unless the driver sets this flag. It
+ * is mandatory for using explicit fences.
If it's mandatory for fences (why is that?), then I guess this patch
should come before any of the fence implementation?
But it's not entirely clear to me what this flag means - ordered with
respect to what? Ordered such that the order in which the buffers are
queued in the driver are the same order that they will be dequeued by
userspace?
I think the order they are queued from userspace can still be
different from both the order they are queued in the driver (because
the in-fences can signal in any order), and dequeued again in
userspace, so "ordered" seems a bit ambiguous.
I think it should be more clear.
Cheers
-Brian
* @fileio: file io emulator internal data, used only if emulator is active
* @threadio: thread io internal data, used only if thread is active
*/
@@ -560,6 +563,7 @@ struct vb2_queue {
unsigned int is_output:1;
unsigned int copy_timestamp:1;
unsigned int last_buffer_dequeued:1;
+ unsigned int ordered:1;
struct vb2_fileio_data *fileio;
struct vb2_threadio_data *threadio;
--
2.13.5
