From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-qt0-f194.google.com ([209.85.216.194]:45845 "EHLO mail-qt0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933277AbdKORLT (ORCPT ); Wed, 15 Nov 2017 12:11:19 -0500 From: Gustavo Padovan To: linux-media@vger.kernel.org Cc: Hans Verkuil , Mauro Carvalho Chehab , Shuah Khan , Pawel Osciak , Alexandre Courbot , Sakari Ailus , Brian Starkey , Thierry Escande , linux-kernel@vger.kernel.org, Gustavo Padovan Subject: [RFC v5 03/11] [media] vb2: add 'ordered_in_driver' property to queues Date: Wed, 15 Nov 2017 15:10:49 -0200 Message-Id: <20171115171057.17340-4-gustavo@padovan.org> In-Reply-To: <20171115171057.17340-1-gustavo@padovan.org> References: <20171115171057.17340-1-gustavo@padovan.org> Sender: linux-media-owner@vger.kernel.org List-ID: From: Gustavo Padovan We use ordered_in_driver property to optimize for the case where the driver can deliver the buffers in an ordered fashion. When it is ordered we can use the same fence context for all fences, but when it is not we need to a new context for each out-fence. So the ordered_in_driver flag will help us with identifying the queues that can be optimized and use the same fence context. v4: make the property a vector for optimization and not a mandatory thing that drivers need to set if they want to use explicit synchronization. v3: improve doc (Hans Verkuil) v2: rename property to 'ordered_in_driver' to avoid confusion Signed-off-by: Gustavo Padovan --- include/media/videobuf2-core.h | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index ef9b64398c8c..38b9c8dd42c6 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -440,6 +440,12 @@ struct vb2_buf_ops { * @fileio_read_once: report EOF after reading the first buffer * @fileio_write_immediately: queue buffer after each write() call * @allow_zero_bytesused: allow bytesused == 0 to be passed to the driver + * @ordered_in_driver: if the driver can guarantee that the queue will be + * ordered or not, i.e., the buffers are dequeued from the driver + * in the same order they are queued to the driver. The default + * is not ordered unless the driver sets this flag. Setting it + * when ordering can be guaranted helps to optimize explicit + * fences. * @quirk_poll_must_check_waiting_for_buffers: Return POLLERR at poll when QBUF * has not been called. This is a vb1 idiom that has been adopted * also by vb2. @@ -510,6 +516,7 @@ struct vb2_queue { unsigned fileio_read_once:1; unsigned fileio_write_immediately:1; unsigned allow_zero_bytesused:1; + unsigned ordered_in_driver:1; unsigned quirk_poll_must_check_waiting_for_buffers:1; struct mutex *lock; -- 2.13.6