[Mesa-dev] [PATCH 2/2] i965/gen: Don't conflate base miplevel in sampler state

[Ben Widawsky]

On Thu, 27 Aug 2015 23:24:26 -0700
Kenneth Graunke <kenneth at whitecape.org> wrote:

> On Thursday, August 27, 2015 11:50:52 AM Ben Widawsky wrote:
> > Gen9 changes the meaning of this to coarse LOD quality mode.
> > Although that's a desirable thing to be setting, it doesn't match
> > the gen8 behavior and this was unintentional.
> > 
> > This doesn't fix, or regress anything on SKL (AFAICT).
> > 
> > Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> > ---
> >  src/mesa/drivers/dri/i965/brw_sampler_state.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/src/mesa/drivers/dri/i965/brw_sampler_state.c
> > b/src/mesa/drivers/dri/i965/brw_sampler_state.c index
> > 2021bb3..b1e339b 100644 ---
> > a/src/mesa/drivers/dri/i965/brw_sampler_state.c +++
> > b/src/mesa/drivers/dri/i965/brw_sampler_state.c @@ -94,11 +94,13 @@
> > brw_emit_sampler_state(struct brw_context *brw, uint32_t
> > border_color_offset) {
> >     ss[0] = BRW_SAMPLER_LOD_PRECLAMP_ENABLE |
> > -           SET_FIELD(base_level, BRW_SAMPLER_BASE_MIPLEVEL) |
> >             SET_FIELD(mip_filter, BRW_SAMPLER_MIP_FILTER) |
> >             SET_FIELD(mag_filter, BRW_SAMPLER_MAG_FILTER) |
> >             SET_FIELD(min_filter, BRW_SAMPLER_MIN_FILTER);
> >  
> > +   if (brw->gen < 9)
> > +      SET_FIELD(base_level, BRW_SAMPLER_BASE_MIPLEVEL);
> > +
> 
> This is broken - SET_FIELD just produces a shifted/masked value.
> You have to actually or it into ss[0] for it to have any effect.

Doh! yeah, I changed this right before sending out (but I did test the
correct code).
> 
> That said, it appears that we pass 0 for base_level in all callers.
> 
> How about a patch that removes the base_level function parameter
> altogether, as well as the SET_FIELD line?
> 

Sounds good to me. I'll get on it. Thanks.

> >     ss[2] = border_color_offset;
> >     if (brw->gen < 6) {
> >        ss[2] += brw->batch.bo->offset64; /* reloc */
> > 
>