From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from osg.samsung.com ([64.30.133.232]:54754 "EHLO osg.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754955AbdKQMQH (ORCPT ); Fri, 17 Nov 2017 07:16:07 -0500 Date: Fri, 17 Nov 2017 10:15:59 -0200 From: Mauro Carvalho Chehab To: Gustavo Padovan Cc: linux-media@vger.kernel.org, Hans Verkuil , Shuah Khan , Pawel Osciak , Alexandre Courbot , Sakari Ailus , Brian Starkey , Thierry Escande , linux-kernel@vger.kernel.org, Gustavo Padovan Subject: Re: [RFC v5 03/11] [media] vb2: add 'ordered_in_driver' property to queues Message-ID: <20171117101559.455cced3@vento.lan> In-Reply-To: <20171115171057.17340-4-gustavo@padovan.org> References: <20171115171057.17340-1-gustavo@padovan.org> <20171115171057.17340-4-gustavo@padovan.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Em Wed, 15 Nov 2017 15:10:49 -0200 Gustavo Padovan escreveu: > 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; As this may depend on the format, it is probably a good idea to set this flag either via a function argument or by a function that would be meant to update it, as video format changes. > unsigned quirk_poll_must_check_waiting_for_buffers:1; > > struct mutex *lock; -- Thanks, Mauro