lima: add new findings to texture descriptor

Lower 8 bits of unknown_1_3 seems to be min_lod,
rest of 4 bits + miplevels are max_lod and min_mipfilter seems to be
lod bias. All are in fixed format with 4 bit integer and 4 bit fraction,
lod_bias also has sign bit.

Blob also seems to do some magic with lod_bias if min filter is nearest --
it adds 0.5 to lod_bias in this case. Same story when all filters are
nearest and mipmapping is enabled, but in this case it subtracts 1/16
from lod_bias.

Fixes 134 dEQP tests in dEQP-GLES2.functional.texture.*

Reviewed-by: Qiang Yu <yuq825@gmail.com>
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3359>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3359>

1 files changed, 18 insertions, 3 deletions

diff --git a/src/gallium/drivers/lima/lima_texture.c b/src/gallium/drivers/lima/lima_texture.c
index b5a6103093c..7f2f81266b6 100644
--- a/src/gallium/drivers/lima/lima_texture.c
+++ b/src/gallium/drivers/lima/lima_texture.c
@@ -118,9 +118,12 @@ lima_update_tex_desc(struct lima_context *ctx, struct lima_sampler_state *sample
                      struct lima_sampler_view *texture, void *pdesc,
                      unsigned desc_size)
 {
+   /* unit is 1/16 since lod_bias is in fixed format */
+   int lod_bias_delta = 0;
    lima_tex_desc *desc = pdesc;
    unsigned first_level;
    unsigned last_level;
+   float max_lod;
 
    memset(desc, 0, desc_size);
 
@@ -144,18 +147,22 @@ lima_update_tex_desc(struct lima_context *ctx, struct lima_sampler_state *sample
    if (last_level - first_level >= LIMA_MAX_MIP_LEVELS)
       last_level = first_level + LIMA_MAX_MIP_LEVELS - 1;
 
-   desc->miplevels = (last_level - first_level);
+   desc->min_lod = lima_float_to_fixed8(sampler->base.min_lod);
+   max_lod = MIN2(sampler->base.max_lod, sampler->base.min_lod +
+                                         (last_level - first_level));
+   desc->max_lod = lima_float_to_fixed8(max_lod);
+   desc->lod_bias = lima_float_to_fixed8(sampler->base.lod_bias);
 
    switch (sampler->base.min_mip_filter) {
       case PIPE_TEX_MIPFILTER_LINEAR:
-         desc->min_mipfilter_1 = 0;
          desc->min_mipfilter_2 = 3;
          break;
       case PIPE_TEX_MIPFILTER_NEAREST:
-         desc->min_mipfilter_1 = 0x1ff;
          desc->min_mipfilter_2 = 0;
          break;
       case PIPE_TEX_MIPFILTER_NONE:
+         desc->max_lod = desc->min_lod;
+         break;
       default:
          break;
    }
@@ -177,6 +184,7 @@ lima_update_tex_desc(struct lima_context *ctx, struct lima_sampler_state *sample
       break;
    case PIPE_TEX_FILTER_NEAREST:
    default:
+      lod_bias_delta = 8;
       desc->min_img_filter_nearest = 1;
       break;
    }
@@ -215,6 +223,13 @@ lima_update_tex_desc(struct lima_context *ctx, struct lima_sampler_state *sample
       break;
    }
 
+   if (desc->min_img_filter_nearest && desc->mag_img_filter_nearest &&
+       desc->min_mipfilter_2 == 0 &&
+       (desc->min_lod != desc->max_lod))
+     lod_bias_delta = -1;
+
+   desc->lod_bias += lod_bias_delta;
+
    lima_texture_desc_set_res(ctx, desc, texture->base.texture,
                              first_level, last_level);
 }