radeonsi: set MIP_POINT_PRECLAMP to 0

This fixes a bug with nearest ("point") mip selection when the fractional
part of max_lod is in (0.5,1). In this case, the spec mandates that
we still select the mip level ceil(max_lod) in the clamping case. However,
MIP_POINT_PRECLAMP will clamp before the mip selection, which is wrong.

Supposedly this setting was originally copied from the closed Vulkan
driver, but as far as I can tell, closed Vulkan was actually changed back
recently :)

Fixes dEQP-GLES3.functional.texture.mipmap.2d.max_lod.{nearest,linear}_nearest

Fixes: f7420ef5b464 ("radeonsi: enable some sampler fields to match the closed driver")
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>

diff --git a/src/gallium/drivers/radeonsi/si_state.c b/src/gallium/drivers/radeonsi/si_state.c
index 96f9e44497783b8e6ceaec998639d5cf989a0452..3135566cd6370ccd902807872dc55542cac75c00 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_state.c
+++ b/src/gallium/drivers/radeonsi/si_state.c
@@ -3991,7 +3991,7 @@ static void *si_create_sampler_state(struct pipe_context *ctx,
                          S_008F38_XY_MAG_FILTER(eg_tex_filter(state->mag_img_filter, max_aniso)) |
                          S_008F38_XY_MIN_FILTER(eg_tex_filter(state->min_img_filter, max_aniso)) |
                          S_008F38_MIP_FILTER(si_tex_mipfilter(state->min_mip_filter)) |
-                         S_008F38_MIP_POINT_PRECLAMP(1) |
+                         S_008F38_MIP_POINT_PRECLAMP(0) |
                          S_008F38_DISABLE_LSB_CEIL(sctx->b.chip_class <= VI) |
                          S_008F38_FILTER_PREC_FIX(1) |
                          S_008F38_ANISO_OVERRIDE(sctx->b.chip_class >= VI));