[Mesa-dev] [RFC] r600g: evergreen/cayman tessellation support

[Aaron Watry]

On Thu, Dec 3, 2015 at 12:57 PM, Dave Airlie <airlied at gmail.com> wrote:

>
> On 4 Dec 2015 03:01, "Aaron Watry" <awatry at gmail.com> wrote:
> >
> > Hi Dave (and others),
> >
> > I cloned your fdo r600g-tess-submit branch and gave it a spin on CEDAR
> (Radeon 5400, kernel 4.3.0) with Heaven, and ran into a few issues.
>
> Just grab r600g-tess-staging
>
> -submit only worked on cayman, but i d posted it here so didn't want to
> change it during review.
>
> Yup, that branch works without modification with the version of heaven in
the phoronix-test-suite.

--Aaron


> Dave.
>
> >
> > 1) Initially, I got an assertion in r600_add_atom stating that the atom
> ID was not less than the R600_NUM_ATOMS value (id = 51, R600_NUM_ATOMS=51).
> >   I bumped R600_NUM_ATOMS to 52 for now, and that got rid of that
> issue... although I have no idea if that was a correct fix.
> >
> > 2) Next, I kept getting a segfault in evergreen_adjust_gprs at line
> 3931. Turns out that rctx->hw_shader_stages[2].shader was null
> (missing/miscompiled GS?).
> >
> > I naively changed the code to the following, and now Heaven actually
> runs with tessellation enabled (and it looks like it's working).
> >
> >     /* gather required shader gprs */
> >     for (i = 0; i < EG_NUM_HW_STAGES; i++) {
> >         if (!rctx->hw_shader_stages[i].shader) {
> >             num_gprs[i] = def_gprs[i];
> >             continue;
> >         }
> >         num_gprs[i] = rctx->hw_shader_stages[i].shader->shader.bc.ngpr;
> >     }
> >
> > Just figured that I'd let you know...
> >
> > If you don't have CEDAR hardware to test with, feel free to ping me to
> test any additional changes.  Note that I didn't run the benchmark to
> completion (too slow, had to get other work done), but it didn't hang my
> GPU in the time that I did have it running.
> >
> > --Aaron
> >
> >
> > On Mon, Nov 30, 2015 at 12:20 AM, Dave Airlie <airlied at gmail.com> wrote:
> >>
> >> Hi,
> >>
> >> Patchbomb time, this set of patches is a first pass at add adding
> >> ARB_tessellation_shader support to the r600g driver. Only Evergreen
> >> and newer GPUs support tessellation. On any of the GPUs that support
> >> native FP64, this will enable OpenGL 4.1 on them.
> >>
> >> The first bunch of patches are a bit of a driver rework to get
> >> things in better shape for tessellation, they shouldn't cause
> >> any regressions.
> >>
> >> This runs heaven on cayman and should pass all the piglits
> >> unless I've done something wrong.
> >>
> >> Development hit two HW programming fun times, one with tess and
> >> dynamic GPR interaction requiring disabling dynamic GPRs, and
> >> one with programming of some SIMD registers to block TESS shaders
> >> on one unit. These fixed most of the hangs we saw during development.
> >>
> >> This doesn't contain SB support yet, Glenn has started working on it.
> >>
> >> Currently tested hw:
> >> working: CAYMAN, REDWOOD, BARTS, TURKS
> >> hangs on any tessellation: CAYMAN
> >> hangs differently at least with heaven: SUMO
> >>
> >> This patchset doesn't block it on any GPUs, but when merged it
> >> probably should.
> >>
> >> Also available at:
> >> http://cgit.freedesktop.org/~airlied/mesa/log/?h=r600g-tess-submit
> >>
> >> Thanks to Glenn Kennard for lots of discussion and testing.
> >>
> >> Dave.
> >>
> >> _______________________________________________
> >> mesa-dev mailing list
> >> mesa-dev at lists.freedesktop.org
> >> http://lists.freedesktop.org/mailman/listinfo/mesa-dev
> >
> >
>
>
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