iris: Don't enable push constants just because there are system values

System values are built-in uniforms.  We set them up as UBO values, and
might pull or push them.  UBO push analysis will take care of that.  We
only want to enable push constants if there's an actual range being
pushed.  Otherwise, we might get into a scenario where 3DSTATE_PS
enables push constants but 3DSTATE_CONSTANT_PS isn't pushing anything.

This fixes GPU hangs in Broadwell image load store tests which have
unused image param system values but no other uniforms.  (We shouldn't
be making those anyway, but that's a separate fix...)

diff --git a/src/gallium/drivers/iris/iris_state.c b/src/gallium/drivers/iris/iris_state.c
index 0a2a5997ab80065668e9b33148bcbd58ff75bcd9..1bdf44693971ff8ddb99926b79d3c71c22bcf89d 100644 (file)
--- a/src/gallium/drivers/iris/iris_state.c
+++ b/src/gallium/drivers/iris/iris_state.c
@@ -3295,8 +3295,7 @@ iris_store_fs_state(struct iris_context *ice,
       ps.FloatingPointMode = prog_data->use_alt_mode;
       ps.MaximumNumberofThreadsPerPSD = 64 - (GEN_GEN == 8 ? 2 : 1);
 
-      ps.PushConstantEnable = shader->num_system_values > 0 ||
-                              prog_data->ubo_ranges[0].length > 0;
+      ps.PushConstantEnable = prog_data->ubo_ranges[0].length > 0;
 
       /* From the documentation for this packet:
        * "If the PS kernel does not need the Position XY Offsets to