Atomic mode-setting drivers

[Daniel Vetter]

Adding relevant mailing lists and people. Please don't send private
mails to maintainers ;-)

On Fri, Mar 4, 2016 at 1:47 PM, Chih-Wei Huang <cwhuang at android-x86.org> wrote:
> Hi Daniel,
> This is the Android-x86 project.
> I'm looking for info about atomic mode-setting drivers
> and then found your presentation at
> http://www.x.org/wiki/Events/XDC2015/Program/xdc-2015.pdf
>
> Especially page 16 talks about the Android support,
> exactly what I want.
>
> It said "no one has an open-source atomic hwc".
> Actually there is one in the AOSP 6.0 release:
>
> https://android.googlesource.com/platform/external/drm_hwcomposer
>
> It's developed by the Chromium team.
> An update repo is here:
> https://chromium.googlesource.com/chromiumos/drm_hwcomposer

Yup, my presentation is already outdated - the latest one for LCA2016
mentions that hwc exists.

> Contributing instructions are here:
> https://sites.google.com/a/chromium.org/dev/contributing-to-drm_hwcomposer
>
> We are trying to enable the drm_hwcomposer for Android-x86.
> However, it requires atomic mode-setting drivers
> which seems are not ready in the vanilla kernel 4.4,
> the kernel we are using now.
>
> Unfortunately none of us is an expert of kernel drm drivres.
> Could you give me a brief status of the
> current atomic mode-setting drivers in vanilla kernel?
> What are still missing? fences? deadlock?
> More important, how much effort do we need
> to make them work with AOSP's drm_hwcomposer?

There's a pile of drivers, but for classic x86 desktop only i915.ko,
and that is still not yet enabled by default. i915.nuclear_pageflip=1
will give you experimental atomic support but not sure whether that's
good enough for hwcomposer.

Fences are being worked on in upstream kernel, but nothing to show
yet.. Otherwise I don't know what's all needed to make it, I haven't
had a chance to play around with it yet.

>
> More discussion about it can be found in
> our devel group:
> https://groups.google.com/d/msg/android-x86-devel/RErWaXk3b7g/g_OSPGf4AwAJ

Please include that mailing list too, to make sure everyone is on board.

Thanks, Daniel
>
> Thank you!
>
> Best regards,
> --
> Chih-Wei
> Android-x86 project
> http://www.android-x86.org



-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch