[Mesa-dev] [PATCH] intel/compiler/gen10: Disable push constants.

[Rafael Antognolli]

We still have gpu hangs on Cannonlake when using push constants, so
disable them for now until we have a proper fix for these hangs.

v2: Add warning message when creating context too.

Signed-off-by: Rafael Antognolli <rafael.antognolli at intel.com>
Cc: Ben Widawsky <ben at bwidawsk.net>
Cc: Kenneth Graunke <kenneth at whitecape.org>
---
 src/intel/compiler/brw_fs.cpp           | 9 +++++++++
 src/mesa/drivers/dri/i965/brw_context.c | 7 +++++++
 2 files changed, 16 insertions(+)

diff --git a/src/intel/compiler/brw_fs.cpp b/src/intel/compiler/brw_fs.cpp
index 3717c50e32a..6d9f0eccb29 100644
--- a/src/intel/compiler/brw_fs.cpp
+++ b/src/intel/compiler/brw_fs.cpp
@@ -2096,6 +2096,15 @@ fs_visitor::assign_constant_locations()
    if (subgroup_id_index >= 0)
       max_push_components--; /* Save a slot for the thread ID */
 
+   /* FIXME: We currently have some GPU hangs that happen apparently when using
+    * push constants. Since we have no solution for such hangs yet, just
+    * go ahead and use pull constants for now.
+    */
+   if (devinfo->gen == 10 && compiler->supports_pull_constants) {
+      compiler->shader_perf_log(log_data, "Disabling push constants.");
+      max_push_components = 0;
+   }
+
    /* We push small arrays, but no bigger than 16 floats.  This is big enough
     * for a vec4 but hopefully not large enough to push out other stuff.  We
     * should probably use a better heuristic at some point.
diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index 126c187f629..b555f7bfdf1 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -1022,6 +1022,13 @@ brwCreateContext(gl_api api,
       return false;
    }
 
+   if (devinfo->gen == 10) {
+      fprintf(stderr,
+              "WARNING: i965 does not fully support Gen10 yet.\n"
+              "Instability or lower performance might occur.\n");
+
+   }
+
    brw_init_state(brw);
 
    intelInitExtensions(ctx);
-- 
2.14.3