From: Hans Verkuil <hverkuil@xs4all.nl>
To: Tomasz Figa <tfiga@chromium.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
Hans Verkuil <hans.verkuil@cisco.com>,
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 Mailing List <linux-media@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [RFC][PATCH 05/15] videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT in REQBUFS
Date: Tue, 28 Jan 2020 09:38:29 +0100 [thread overview]
Message-ID: <be0b79dc-c92f-cbb5-2baa-b058a944435d@xs4all.nl> (raw)
In-Reply-To: <CAAFQd5C=Zj7h5Xe1w=0czX5ge1Kh=2cj6yEkN6binPgmmpj6Wg@mail.gmail.com>
On 1/28/20 5:45 AM, Tomasz Figa wrote:
> On Thu, Jan 23, 2020 at 8:08 PM Hans Verkuil <hverkuil@xs4all.nl> wrote:
>>
>> On 1/22/20 4:48 AM, Sergey Senozhatsky wrote:
>>> On (20/01/22 11:18), Sergey Senozhatsky wrote:
>>> [..]
>>>>>> + * -
>>>>>> + - __u32
>>>>>> - ``reserved``\ [1]
>>>>>> - A place holder for future extensions. Drivers and applications
>>>>>> - must set the array to zero.
>>>>>> + must set the array to zero, unless application wants to specify
>>>>>> + buffer management ``flags``.
>>>>>
>>>>> I think support for this flag should be signaled as a V4L2_BUF_CAP capability.
>>>>> If the capability is not set, then vb2 should set 'flags' to 0 to preserve the
>>>>> old 'Drivers and applications must set the array to zero' behavior.
>>>>
>>>> The patch set adds V4L2_BUF_CAP_SUPPORTS_CACHE_HINTS towards the end of the
>>>> series, I guess I can shuffle the patches and change the wording here.
>>>
>>> Or I can add separate queue flag and V4L2_BUF_CAP:
>>>
>>> struct vb2_queue {
>>> ...
>>> allow_cache_hints:1
>>> + allow_consistency_hints:1
>>> ...
>>> }
>>>
>>> and then have CAP_SUPPORTS_CACHE_HINTS/CAP_SUPPORTS_CONSISTENCY_HINTS.
>>
>> Don't these two go hand-in-hand? I.e. either neither are supported, or
>> both are supported? If so, then one queue flag is sufficient.
>
> Cache sync hints are already part of the standard UAPI, so I think
> there isn't any capability bit needed for them.
These hints may exist, but they never worked. So I think a capability would
be very useful.
That said, they aren't
> really tied to non-consistent MMAP buffers. Userspace using USERPTR
> can also use them.
OK, two separate capability bits is fine.
Regards,
Hans
>
> MMAP buffer consistency hint deserves a capability bit indeed.
>
> Best regards,
> Tomasz
>
next prev parent reply other threads:[~2020-01-28 8:38 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 [this message]
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
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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