zink: delete need_blend_constants

this is an artifact of very old code before the dynamic state was set
for all graphics pipelines

now the checks only cause blend constants to not be updated, which triggers
bugs and validation failures

cc: mesa-stable

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20799>
(cherry picked from commit b4d18f2ad1)

.pick_status.json

@@ -2083,7 +2083,7 @@
         "description": "zink: delete need_blend_constants",
         "nominated": true,
         "nomination_type": 0,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": null
     },

src/gallium/drivers/zink/zink_draw.cpp

@@ -736,8 +736,7 @@ zink_draw(struct pipe_context *pctx,
       ctx->sample_locations_changed = false;
    }
 
-   if ((BATCH_CHANGED || ctx->blend_state_changed) &&
-       ctx->gfx_pipeline_state.blend_state->need_blend_constants) {
+   if (BATCH_CHANGED || ctx->blend_state_changed) {
       VKCTX(CmdSetBlendConstants)(batch->state->cmdbuf, ctx->blend_constants);
    }
    ctx->blend_state_changed = false;

src/gallium/drivers/zink/zink_state.c

@@ -280,21 +280,6 @@ blend_factor(enum pipe_blendfactor factor)
 }
 
 
-static bool
-need_blend_constants(enum pipe_blendfactor factor)
-{
-   switch (factor) {
-   case PIPE_BLENDFACTOR_CONST_COLOR:
-   case PIPE_BLENDFACTOR_CONST_ALPHA:
-   case PIPE_BLENDFACTOR_INV_CONST_COLOR:
-   case PIPE_BLENDFACTOR_INV_CONST_ALPHA:
-      return true;
-
-   default:
-      return false;
-   }
-}
-
 static VkBlendOp
 blend_op(enum pipe_blend_func func)
 {
@@ -371,8 +356,6 @@ zink_create_blend_state(struct pipe_context *pctx,
    cso->alpha_to_coverage = blend_state->alpha_to_coverage;
    cso->alpha_to_one = blend_state->alpha_to_one;
 
-   cso->need_blend_constants = false;
-
    for (int i = 0; i < blend_state->max_rt + 1; ++i) {
       const struct pipe_rt_blend_state *rt = blend_state->rt;
       if (blend_state->independent_blend_enable)
@@ -388,12 +371,6 @@ zink_create_blend_state(struct pipe_context *pctx,
          att.srcAlphaBlendFactor = blend_factor(fix_blendfactor(rt->alpha_src_factor, cso->alpha_to_one));
          att.dstAlphaBlendFactor = blend_factor(fix_blendfactor(rt->alpha_dst_factor, cso->alpha_to_one));
          att.alphaBlendOp = blend_op(rt->alpha_func);
-
-         if (need_blend_constants(rt->rgb_src_factor) ||
-             need_blend_constants(rt->rgb_dst_factor) ||
-             need_blend_constants(rt->alpha_src_factor) ||
-             need_blend_constants(rt->alpha_dst_factor))
-            cso->need_blend_constants = true;
       }
 
       if (rt->colormask & PIPE_MASK_R)

src/gallium/drivers/zink/zink_types.h

@@ -318,7 +318,6 @@ struct zink_blend_state {
    VkBool32 alpha_to_coverage;
    VkBool32 alpha_to_one;
 
-   bool need_blend_constants;
    bool dual_src_blend;
 };