i965: Revert Gen8 aspect of VF PIPE_CONTROL workaround.

This apparently causes hangs on Broadwell, so let's back it out for now.
I think there are other PIPE_CONTROL workarounds that we're missing.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103787

diff --git a/src/mesa/drivers/dri/i965/brw_pipe_control.c b/src/mesa/drivers/dri/i965/brw_pipe_control.c
index c6e7dd15f4c719fdf363b8189ac6c3527df3e57e..e28be34c8e814f806e82ad54f8755495affdb6a3 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_pipe_control.c
+++ b/src/mesa/drivers/dri/i965/brw_pipe_control.c
@@ -135,7 +135,7 @@ brw_emit_pipe_control(struct brw_context *brw, uint32_t flags,
             brw_emit_pipe_control_flush(brw, 0);
          }
 
-         if (devinfo->gen >= 8) {
+         if (devinfo->gen >= 9) {
             /* THE PIPE_CONTROL "VF Cache Invalidation Enable" docs continue:
              *
              *    "Project: BDW+
@@ -146,6 +146,10 @@ brw_emit_pipe_control(struct brw_context *brw, uint32_t flags,
              *
              * If there's a BO, we're already doing some kind of write.
              * If not, add a write to the workaround BO.
+             *
+             * XXX: This causes GPU hangs on Broadwell, so restrict it to
+             *      Gen9+ for now...see this bug for more information:
+             *      https://bugs.freedesktop.org/show_bug.cgi?id=103787
              */
             if (!bo) {
                flags |= PIPE_CONTROL_WRITE_IMMEDIATE;