[PATCH v3 0/3] drm/vkms: Add support for multiple pipes

[Jim Shargo]

Hey, all!

I am so excited to see other folks excited about extending VKMS. I
think it's a great project and has outstanding potential!

Life stuff made me AFK for the last few months, but I'm back now and
I've been wrapping up the work on the patchset Brandon linked.

The current WIP patches are here:
https://gitlab.freedesktop.org/jshargo/compositor-kernel-explorations/-/merge_requests/4

They even come with matching IGT tests!
https://gitlab.freedesktop.org/jshargo/igt-gpu-tools/-/commit/8375cf128f0811d54ecb4a0b5cf044942ffc67b9

I'm hoping to send them out again soon, hopefully next week.

As a suggestion for how to move forward: the first three patches are
little refactors that are separable from the core ConfigFS ones (which
might have more back-and-forth design iterations). With those three,
the param you're adding should be easy to put on top. I can try to get
those out sooner for review.

What do you think?


On Thu, Apr 27, 2023 at 10:51 PM Brandon Ross Pollack
<brpol at chromium.org> wrote:
>
> I'm adding the original offer of those changes.  We talked recently
> and they have the intent to push forward and merge them.  I'm still
> getting up to speed a bit, but I will probably have a stronger opinion
> by early next week.
>
>
> On Wed, Apr 26, 2023 at 9:54 PM Marius Vlad <marius.vlad at collabora.com> wrote:
> >
> > Hi Brandon, Xie,
> >
> > Thanks for reaching out, and for the heads-up. I need to take a closer
> > look, but by glancing over it, using configFS would be really awesome.
> > Think we could really benefit from having that in our CI and being able
> > to customize the entire pipeline. I'm totally for that.
> >
> > It looks like it requires some infra work so I guess landing that might
> > require quite a bit of time. Not sure if there are recent updates for it.
> >
> > My changes are quite trivial and much more focused on just having
> > multiple virtual displays, so IDK, I've submitted a version that seems
> > to work, so I guess others should or would decide if we should drop mine
> > and focus on the configFS series, or we should go with configFS as a
> > follow-up. Would have liked to get something in the tree so we can at
> > least have something to work with.
> >
> > Thoughts on the matter on how should we go about it?
> >
> > On 4/26/23 05:06, Brandon Ross Pollack wrote:
> > > We're doing/planning on doing similar or related work here at chromium.
> > >
> > > https://patchwork.kernel.org/project/dri-devel/list/?series=662676&submitter=&state=&q=&delegate=&archive=both <https://patchwork.kernel.org/project/dri-devel/list/?series=662676&submitter=&state=&q=&delegate=&archive=both>
> > >
> > > Here's the stuff we have now (we're currently rebasing and touching it
> > > up, myself and @Yi Xie <mailto:yixie at google.com> will be taking over
> > > this work.
> > >
> > > Our plans are to add configFS changes and DRI VKMS changes to be able to
> > > add and remove virtual displays at runtime (among other things needed
> > > for our own testing purposes for our Exo wayland implementation).
> > >
> > > We're still learning how this all works and comes together, but it is
> > > worth letting you know "us too"
> > >
> > > We can chat more and see where we overlap and can learn from each other :)
> > >
> > > On Tue, Apr 25, 2023 at 4:30 PM Marius Vlad <marius.vlad at collabora.com
> > > <mailto:marius.vlad at collabora.com>> wrote:
> > >
> > >     With multiple pipe available we can perform management of outputs at
> > >     a more granular level, such that we're able to turn off or on several
> > >     outputs at a time, or combinations that arise from doing that.
> > >
> > >     The Weston project use VKMS when running its test suite in CI, and we
> > >     have now uses cases which would need to ability to set-up the outputs
> > >     DPMS/state individually, rather than globally -- which would affect all
> > >     outputs. This an attempt on fixing that by giving the possibility to
> > >     create more than one pipe, and thus allowing to run tests that could
> > >     exercise code paths in the compositor related to management of outputs.
> > >
> > >     v3:
> > >        - Apply the series against drm-misc-next (Maíra Canal)
> > >        - Add a lower range check to avoid passing negative values to
> > >        max_pipes (Maíra Canal)
> > >
> > >     v2:
> > >        - Replace 'outputs' with 'pipes' as to use the proper terminology
> > >          (Thomas Zimmermann, Maíra Canal)
> > >        - Fixed passing wrong possible_crtc bitmask when initializing the
> > >          write back connector which address kms_writeback failure (Maíra
> > >     Canal)
> > >        - Add a feat. note about moving overlay planes between CRTCs
> > >     (Melissa Wen)
> > >
> > >     Marius Vlad (3):
> > >        vkms: Pass the correct bitmask for possible crtcs
> > >        vkms: Add support for multiple pipes
> > >        Documentation/gpu/vkms.rst: Added a note about plane migration
> > >
> > >       Documentation/gpu/vkms.rst            |  5 +++--
> > >       drivers/gpu/drm/vkms/vkms_crtc.c      |  3 +--
> > >       drivers/gpu/drm/vkms/vkms_drv.c       | 31 +++++++++++++++++++++------
> > >       drivers/gpu/drm/vkms/vkms_drv.h       | 12 ++++++++---
> > >       drivers/gpu/drm/vkms/vkms_output.c    |  7 +++---
> > >       drivers/gpu/drm/vkms/vkms_writeback.c | 24 ++++++++++-----------
> > >       6 files changed, 53 insertions(+), 29 deletions(-)
> > >
> > >     --
> > >     2.39.2
> > >