Re: [linux-sunxi] Cedrus driver

From: Hans Verkuil <hverkuil@xs4all.nl>
To: Giulio Benetti <giulio.benetti@micronovasrl.com>,
	Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Andreas Baierl <list@imkreisrum.de>,
	linux-sunxi <linux-sunxi@googlegroups.com>,
	linux@armlinux.org.uk, wens@csie.org,
	linux-kernel@vger.kernel.org, thomas@vitsch.nl,
	linux-media@vger.kernel.org
Subject: Re: [linux-sunxi] Cedrus driver
Date: Thu, 16 Nov 2017 14:12:28 +0100	[thread overview]
Message-ID: <6f94505d-69bb-6688-4b13-6a0ed2af8dd4@xs4all.nl> (raw)
In-Reply-To: <e03cfdb5-57b3-fefd-75c3-6b97348682ff@micronovasrl.com>

On 16/11/17 13:57, Giulio Benetti wrote:
> Il 16/11/2017 13:53, Maxime Ripard ha scritto:
>> On Thu, Nov 16, 2017 at 01:30:52PM +0100, Giulio Benetti wrote:
>>>> On Thu, Nov 16, 2017 at 11:37:30AM +0100, Giulio Benetti wrote:
>>>>> Il 16/11/2017 11:31, Andreas Baierl ha scritto:
>>>>>> Am 16.11.2017 um 11:13 schrieb Giulio Benetti:
>>>>>>> Hello,
>>>>>>>
>>>>>> Hello,
>>>>>>> I'm wondering why cedrus
>>>>>>> https://github.com/FlorentRevest/linux-sunxi-cedrus has never been
>>>>>>> merged with linux-sunxi sunxi-next.
>>>>>>>
>>>>>> Because it is not ready to be merged. It depends on the v4l2 request
>>>>>> API, which was not merged and which is re-worked atm.
>>>>>> Also, sunxi-cedrus itself is not in a finished state and is not as
>>>>>> feature-complete to be merged. Anyway it might be something for
>>>>>> staging... Has there been a [RFC] on the mailing list at all?
>>>>>
>>>>> Where can I find a list of TODOs to get it ready to be merged?
>>>>
>>>> Assuming that the request API is in, we'd need to:
>>>>     - Finish the MPEG4 support
>>>>     - Work on more useful codecs (H264 comes to my mind)
>>>>     - Implement the DRM planes support for the custom frame format
>>>>     - Implement the DRM planes support for scaling
>>>>     - Test it on more SoCs
>>>>
>>>> Or something along those lines.
>>>
>>> Lot of work to do
>>
>> Well... If it was fast and easy it would have been done already :)
> 
> :))
> 
>>
>>>>>>> I see it seems to be dead, no commit in 1 year.
>>>>>>
>>>>>> Yes, because the author did this during an internship, which ended ...
>>>>>> Afaik nobody picked up his work yet.
>>>>
>>>> That's not entirely true. Some work has been done by Thomas (in CC),
>>>> especially on the display engine side, but last time we talked his
>>>> work was not really upstreamable.
>>>>
>>>> We will also resume that effort starting next march.
>>>
>>> Is it possible a preview on a separate Reporitory to start working on now?
>>> Expecially to start porting everything done by FlorentRevest to mainline,
>>> admitted you've not already done.
>>
>> I'm not sure what you're asking for. Florent's work *was* on mainline.
> 
> and then they took it off because it was unmantained?
> You've spoken about Thomas(in CC) not ready,
> maybe I could help on that if it's public to accelerate.
> If I'm able to of course, this is my primary concern.
> 
> Otherwise, in which way can I help improving it to make it accept to linux-sunxi?
> Starting from Florent's work and porting it to sunxi-next to begin?
> And after that adding all features you've listed?
> Tell me what I can do(I repeat, if I'm able to).

The bottleneck is that the Request API is not mainlined. We restarted work
on it after a meeting a few weeks back where we all agreed on the roadmap
so hopefully it will go into mainline Q1 or Q2 next year.

That said, you can use Florent's patch series for further development.
It should be relatively easy to convert it to the final version of the
Request API. Just note that the public API of the final Request API will
be somewhat different from the old version Florent's patch series is using.

Regards,

	Hans

> 
>>
>> Maxime
>>
> 
> Thank you
> 