[Mesa-dev] [PATCH 4/4] i965/gen10: Implement Wa3DStateMode

[Jason Ekstrand]

On Wed, Oct 4, 2017 at 3:11 PM, Anuj Phogat <anuj.phogat at gmail.com> wrote:

> On Mon, Oct 2, 2017 at 7:46 PM, Jason Ekstrand <jason at jlekstrand.net>
> wrote:
> > On Mon, Oct 2, 2017 at 4:08 PM, Anuj Phogat <anuj.phogat at gmail.com>
> wrote:
> >>
> >> Cc: mesa-stable at lists.freedesktop.org
> >> Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
> >> ---
> >>  src/mesa/drivers/dri/i965/brw_state_upload.c | 7 +++++--
> >>  1 file changed, 5 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/src/mesa/drivers/dri/i965/brw_state_upload.c
> >> b/src/mesa/drivers/dri/i965/brw_state_upload.c
> >> index a1bf54dc72..c224355a2b 100644
> >> --- a/src/mesa/drivers/dri/i965/brw_state_upload.c
> >> +++ b/src/mesa/drivers/dri/i965/brw_state_upload.c
> >> @@ -88,8 +88,11 @@ brw_upload_initial_gpu_state(struct brw_context
> *brw)
> >>     if (devinfo->gen == 10) {
> >>        BEGIN_BATCH(2);
> >>        OUT_BATCH(_3DSTATE_3D_MODE  << 16 | (2 - 2));
> >> -      OUT_BATCH(GEN10_FLOAT_BLEND_OPTIMIZATION_ENABLE << 16 |
> >> -                GEN10_FLOAT_BLEND_OPTIMIZATION_ENABLE);
> >> +      /* From gen10 workaround table in h/w specs:
> >> +       * "On 3DSTATE_3D_MODE, driver must always program bits 31:16 of
> >> DW1
> >> +       *  a value of 0xFFFF"
> >> +       */
> >> +      OUT_BATCH(0xFFFF << 16 | GEN10_FLOAT_BLEND_OPTIMIZATION_ENABLE);
> >
> >
> > Bits 31:16 are the mask bits.  By programming them to 0xFFFF, you're
> making
> > it write the entire register and not just the float blend optimization
> > enable bit.  If we're going to do that, we need to figure out what
> values we
> > want in the other fields and always set them along with the float blend
> > optimization enable bit.
> >
> Right. After looking at all other fields, I don't think we want to set
> any of them except one. That field is "Slice Hashing Table Enable" which
> says:
> "For gen10, when the total number of subslices enabled is 6,8,10, or
> 12, slice hashing table must be enabled."
>
> I have no idea about slice hashing tables and I think enabling it
> should be handled in a separate patch anyways.
>

What I wonder is what we're using today.  I don't think mesa is actually
setting anything other than the default right now but Ken was looking into
it at one point.
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