[git pull] drm for 5.8-rc1

[Karol Herbst]

On Wed, Aug 12, 2020 at 12:43 PM Karol Herbst <kherbst at redhat.com> wrote:
>
> On Wed, Aug 12, 2020 at 12:27 PM Karol Herbst <kherbst at redhat.com> wrote:
> >
> > On Wed, Aug 12, 2020 at 2:19 AM James Jones <jajones at nvidia.com> wrote:
> > >
> > > Sorry for the slow reply here as well.  I've been in the process of
> > > rebasing and reworking the userspace patches.  I'm not clear my changes
> > > will address the Jetson Nano issue, but if you'd like to try them, the
> > > latest userspace changes are available here:
> > >
> > >    https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3724
> > >
> > > And the tegra-drm kernel patches are here:
> > >
> > >
> > > https://patchwork.ozlabs.org/project/linux-tegra/patch/20191217005205.2573-1-jajones@nvidia.com/
> > >
> > > Those + the kernel changes addressed in this thread are everything I had
> > > outstanding.
> > >
> >
> > I don't know if that's caused by your changes or not, but now the
> > assert I hit is a different one pointing out that
> > nvc0_miptree_select_best_modifier fails in a certain case and returns
> > MOD_INVALID... anyway, it seems like with your patches applied it's
> > now way easier to debug and figure out what's going wrong, so maybe I
> > can figure it out now :)
> >
>
> collected some information which might help to track it down.
>
> src/gallium/frontends/dri/dri2.c:648 is the assert hit: assert(*zsbuf)
>
> templ is {reference = {count = 0}, width0 = 300, height0 = 300, depth0
> = 1, array_size = 1, format = PIPE_FORMAT_Z24X8_UNORM, target =
> PIPE_TEXTURE_2D, last_level = 0, nr_samples = 0, nr_storage_samples =
> 0, usage = 0, bind = 1, flags = 0, next = 0x0, screen = 0x0}
>
> inside tegra_screen_resource_create modifier says
> DRM_FORMAT_MOD_INVALID as template->bind is 1
>
> and nvc0_miptree_select_best_modifier returns DRM_FORMAT_MOD_INVALID,
> so the call just returns NULL leading to the assert.
>
> Btw, this is on Xorg-1.20.8-1.fc32.aarch64 with glxgears.
>

So I digged a bit deeper and here is what tripps it of:

when the context gets made current, the normal framebuffer validation
and render buffer allocation is done, but we end up inside
tegra_screen_resource_create at some point with PIPE_BIND_SCANOUT set
in template->bind. Now the tegra driver forces the
DRM_FORMAT_MOD_LINEAR modifier and calls into
resource_create_with_modifiers.

If it wouldn't do that, nouveau would allocate a tiled buffer, with
that it's linear and we at some point end up with an assert about a
depth_stencil buffer being there even though it shouldn't. If I always
use DRM_FORMAT_MOD_INVALID in tegra_screen_resource_create, things
just work.

That's kind of the cause I pinpointed the issue down to. But I have no
idea what's supposed to happen and what the actual bug is.

> > > Thanks,
> > > -James
> > >
> > > On 8/4/20 1:58 AM, Karol Herbst wrote:
> > > > Hi James,
> > > >
> > > > I don't know if you knew, but on the Jetson nano we had the issue for
> > > > quite some time, that GLX/EGL through mesa on X was broken due to some
> > > > fix in mesa related to modifiers.
> > > >
> > > > And I was wondering if the overall state just caused the issue we saw
> > > > here and wanted to know what branches/patches I needed for the various
> > > > projects to see if the work you have been doing since the last
> > > > upstream nouveau regression would be of any help here?
> > > >
> > > > Mind pointing me towards everything I'd need to check that?
> > > >
> > > > I'd really like to fix this, but didn't have the time to investigate
> > > > what the core problem here was, but I think it's very likely that a
> > > > fixed/improved modifier support could actually fix it as well.
> > > > Alternately I'd like to move to kmsro in mesa as this fixes it as
> > > > well, but that could just be by coincidence and would break other
> > > > devices..
> > > >
> > > > Thanks
> > > >
> > > > On Tue, Jul 14, 2020 at 4:32 PM James Jones <jajones at nvidia.com> wrote:
> > > >>
> > > >> Still testing.  I'll get a Sign-off version out this week unless I find
> > > >> a problem.
> > > >>
> > > >> Thanks,
> > > >> -James
> > > >>
> > > >> On 7/12/20 6:37 PM, Dave Airlie wrote:
> > > >>> How are we going with a fix for this regression I can commit?
> > > >>>
> > > >>> Dave.
> > > >>>
> > > >> _______________________________________________
> > > >> dri-devel mailing list
> > > >> dri-devel at lists.freedesktop.org
> > > >> https://lists.freedesktop.org/mailman/listinfo/dri-devel
> > > >>
> > > >
> > >