From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
Hans Verkuil <hans.verkuil@cisco.com>,
Tomasz Figa <tfiga@chromium.org>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Kyungmin Park <kyungmin.park@samsung.com>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Sakari Ailus <sakari.ailus@iki.fi>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Pawel Osciak <posciak@chromium.org>,
linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH 13/15] videobuf2: do not sync buffers for DMABUF queues
Date: Fri, 24 Jan 2020 11:25:44 +0900 [thread overview]
Message-ID: <20200124022544.GD158382@google.com> (raw)
In-Reply-To: <57f711a0-6183-74f6-ab24-ebe414cb6881@xs4all.nl>
On (20/01/23 12:35), Hans Verkuil wrote:
> On 1/22/20 6:05 AM, Sergey Senozhatsky wrote:
> > On (20/01/10 11:30), Hans Verkuil wrote:
[..]
> But whatever was written in the buffer is going to be overwritten anyway.
>
> Unless I am mistaken the current situation is that the cache syncs are done
> in both prepare and finish, regardless of the DMA direction.
>
> I would keep that behavior to avoid introducing any unexpected regressions.
OK.
> Then, if q->allow_cache_hint is set, then default to a cache sync (cache clean)
> in the prepare for OUTPUT buffers and a cache sync (cache invalidate) in the
> finish for CAPTURE buffers.
We alter default cache sync behaviour based both on queue ->memory
type and queue ->dma_dir. Shall both of those cases depend on
->allow_cache_hints, or q->memory can be independent?
static void set_buffer_cache_hints(struct vb2_queue *q,
struct vb2_buffer *vb,
struct v4l2_buffer *b)
{
if (!q->allow_cache_hints)
return;
/*
* DMA exporter should take care of cache syncs, so we can avoid
* explicit ->prepare()/->finish() syncs. For other ->memory types
* we always need ->prepare() or/and ->finish() cache sync.
*/
if (q->memory == VB2_MEMORY_DMABUF) {
vb->need_cache_sync_on_finish = 0;
vb->need_cache_sync_on_prepare = 0;
return;
}
/*
* ->finish() cache sync can be avoided when queue direction is
* TO_DEVICE.
*/
if (q->dma_dir == DMA_TO_DEVICE)
vb->need_cache_sync_on_finish = 0;
else
vb->need_cache_sync_on_finish = 1;
/*
* ->prepare() cache sync can be avoided when queue direction is
* FROM_DEVICE.
*/
if (q->dma_dir == DMA_FROM_DEVICE)
vb->need_cache_sync_on_prepare = 0;
else
vb->need_cache_sync_on_prepare = 1;
if (b->flags & V4L2_BUF_FLAG_NO_CACHE_INVALIDATE)
vb->need_cache_sync_on_finish = 0;
if (b->flags & V4L2_BUF_FLAG_NO_CACHE_CLEAN)
vb->need_cache_sync_on_prepare = 0;
}
next prev parent reply other threads:[~2020-01-24 2:26 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-17 3:20 [RFC][PATCH 00/15] Implement V4L2_BUF_FLAG_NO_CACHE_* flags Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 01/15] videobuf2: add cache management members Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 02/15] videobuf2: handle V4L2 buffer cache flags Sergey Senozhatsky
2020-01-10 10:24 ` Hans Verkuil
2020-01-22 1:39 ` Sergey Senozhatsky
2020-01-22 2:53 ` Sergey Senozhatsky
2020-01-28 4:35 ` Tomasz Figa
2019-12-17 3:20 ` [RFC][PATCH 03/15] videobuf2: add V4L2_FLAG_MEMORY_NON_CONSISTENT flag Sergey Senozhatsky
2020-01-10 9:36 ` Hans Verkuil
2020-01-10 9:46 ` Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 04/15] videobuf2: add queue memory consistency parameter Sergey Senozhatsky
2020-01-10 9:47 ` Hans Verkuil
2020-01-22 2:05 ` Sergey Senozhatsky
2020-01-23 11:02 ` Hans Verkuil
2020-01-24 2:04 ` Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 05/15] videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT in REQBUFS Sergey Senozhatsky
2020-01-10 9:55 ` Hans Verkuil
2020-01-22 2:18 ` Sergey Senozhatsky
2020-01-22 3:48 ` Sergey Senozhatsky
2020-01-23 11:08 ` Hans Verkuil
2020-01-28 4:45 ` Tomasz Figa
2020-01-28 8:38 ` Hans Verkuil
2019-12-17 3:20 ` [RFC][PATCH 06/15] videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT in CREATE_BUFS Sergey Senozhatsky
2020-01-10 9:59 ` Hans Verkuil
2020-01-23 3:41 ` Sergey Senozhatsky
2020-01-23 11:41 ` Hans Verkuil
2020-01-24 1:28 ` Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 07/15] videobuf2: factor out planes prepare/finish functions Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 08/15] videobuf2: do not sync caches when we are allowed not to Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 09/15] videobuf2: check ->synced flag in prepare() and finish() Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 10/15] videobuf2: let user-space know when driver supports cache hints Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 11/15] videobuf2: add begin/end cpu_access callbacks to dma-contig Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 12/15] videobuf2: add begin/end cpu_access callbacks to dma-sg Sergey Senozhatsky
2020-01-10 10:13 ` Hans Verkuil
2020-01-22 6:37 ` Sergey Senozhatsky
2020-01-28 4:38 ` Tomasz Figa
2020-01-28 8:36 ` Hans Verkuil
2020-01-30 11:02 ` Tomasz Figa
2020-01-30 12:18 ` Hans Verkuil
2020-02-03 10:04 ` Tomasz Figa
2020-02-04 2:50 ` Sergey Senozhatsky
2020-02-06 8:51 ` Tomasz Figa
2019-12-17 3:20 ` [RFC][PATCH 13/15] videobuf2: do not sync buffers for DMABUF queues Sergey Senozhatsky
2020-01-10 10:30 ` Hans Verkuil
2020-01-22 5:05 ` Sergey Senozhatsky
2020-01-23 11:35 ` Hans Verkuil
2020-01-24 2:25 ` Sergey Senozhatsky [this message]
2020-01-24 7:32 ` Sergey Senozhatsky
2020-01-28 7:22 ` Tomasz Figa
2020-01-28 7:34 ` Sergey Senozhatsky
2020-01-28 7:19 ` Tomasz Figa
2020-01-28 8:47 ` Hans Verkuil
2019-12-17 3:20 ` [RFC][PATCH 14/15] videobuf2: don't test db_attach in dma-contig prepare and finish Sergey Senozhatsky
2020-01-10 10:32 ` Hans Verkuil
2019-12-17 3:20 ` [RFC][PATCH 15/15] videobuf2: don't test db_attach in dma-sg " Sergey Senozhatsky
2020-01-08 2:27 ` [RFC][PATCH 00/15] Implement V4L2_BUF_FLAG_NO_CACHE_* flags Sergey Senozhatsky
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