[Mesa-dev] About drm_hwcomposer (Was Re: About the PixelFormat mappings in drm_gralloc)

[Sean Paul]

On Wed, Jan 20, 2016 at 8:49 PM, Chih-Wei Huang <cwhuang at android-x86.org>
wrote:

> CC to the android-x86 devel list so more developers can follow.
>
> 2016-01-21 6:19 GMT+08:00 Rob Clark <robdclark at gmail.com>:
> > On Wed, Jan 20, 2016 at 4:59 PM, Rob Herring <robh at kernel.org> wrote:
> >> Hi Sean,
> >>
> >> On Thu, Jan 14, 2016 at 1:15 PM, Sean Paul <seanpaul at chromium.org>
> wrote:
> >>>
> >>>
> >>> On Thu, Jan 14, 2016 at 9:47 AM, Chih-Wei Huang <
> cwhuang at android-x86.org>
> >>> wrote:
> >>>>
> >>>> Hello Sean,
> >>>> My last try of drm_hwcomposer failed due to
> >>>> my limited time and knowledge.
> >>>>
> >>>> Fortunately more developers join us
> >>>> to work on this topic now, including
> >>>> Rob Herring (kernel drm developer),
> >>>> Rob Clark and Emil Velikov (Mesa developers)
> >>>> We are working on drm_hwcomposer
> >>>> for virtio-gpu, the emulated GPU for QEMU.
> >>>>
> >>>> If you don't mind, I would invite you to join
> >>>> our devel group for the discussion.
> >>>
> >>>
> >>> [adding Emil, Rob, and Rob]
> >>>
> >>> Hi,
> >>> Ok, I've signed up for the android-x86 list. I don't anticipate seeing
> all
> >>> posts, so please cc me on threads needing feedback.
> >>>
> >>> We also just today open-sourced drm_hwcomposer on the chromium gerrit
> >>> instance, such that we'll be doing all of our development in the open
> on
> >>> that repo.
> >>>
> >>> The repo is here:
> >>> https://chromium.googlesource.com/chromiumos/drm_hwcomposer
> >>>
> >>> Contributing instructions are here:
> >>>
> https://sites.google.com/a/chromium.org/dev/contributing-to-drm_hwcomposer
> >>
> >> Thanks for the pointer. This is essentially what I'm based on.
> >>
> >> Is there a testing target we need to use for submitting patches? Pixel
> >> C? The first problem is the use of the pre mainline atomic functions,
>
> Dear Sean,
> I echo Rob's words.
> We planned to use kernel 4.4 and libdrm 2.4.66+
> for marshmallow-x86.
> Do you have an updated drm_gralloc that
> can work with libdrm 2.4.66+?
>

No.



> Or do you hope me to submit a patch for it?
>
> >> so using mainline kernel and libdrm are a problem. What is your plan
> >> to handle that?
>

I'll look at updating android's libdrm today. In the long term, we're
hoping to centralize libdrm between cros and android much like
drm_hwcomposer, but there are still some moving parts that have yet to be
sorted out.

Once libdrm is updated, we can look at getting robh's patch in.


>> It also no longer works with the drm_gralloc in AOSP due to missing
> >> GRALLOC_MODULE_PERFORM_GET_USAGE support, so is there any plan to also
> >> host drm_gralloc?
> >
>

To be honest, I don't think we have any plans to use drm_gralloc, so I'm
not sure where it'll be hosted in the future.

For the time being, I think adding a stub to drm_gralloc to implement this
call might be the best solution.


> Just my own $0.02, but I would really like to move drm_gralloc into
> > mesa.. or at least the gallium pipe-driver part.
> >
> > Having gralloc essentially being a sort of state-tracker is great for
> > a lot of reasons.. ie. don't have to add new gralloc specific code for
> > new drivers like freedreno/vc4/etnaviv, and also by sharing a common
> > pipe_screen we can avoid some refcnt'ing / handle lifecycle issues.
> >
> > But that also means using API's which aren't really intended to be
> > exposed outside of mesa.  Ie. gallium is not intended to be consumed
> > as a stable API from external state trackers.
> >
> > I know that chromium had started adding support for some other
> > non-mesa drivers.  I'm not sure how best to handle that.  Maybe what
> > makes most sense is to just copy/paste some code into mesa, and leave
> > external drm_gralloc just for blob drivers..
> >
> > (I was kinda hoping Emil would someday tackle moving the code into
> > mesa, since whenever I mess with mesa build system I make a mess of
> > things :-P)
> >
> > BR,
> > -R
> >
> >> Anything you can share about planned changes/features you are working
> >> on so we can better coordinate work Linaro is doing here.
>

I've been kicking around multi-monitor support for a while, and have some
WIP patches. I can ping you when I post them to gerrit.

Aside from that, I know zachr (cc'd) is playing around with some cleanup
stuff, I'm not sure whether he has anything concrete.

Sean


>>
> >> Rob
>
>
>
> --
> Chih-Wei
> Android-x86 project
> http://www.android-x86.org
>
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