Mesa (staging/20.0): iris: Apply the flushes when switching pipelines.

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Module: Mesa
Branch: staging/20.0
Commit: 3aafc6ab8fa8421b17302478105e807a1e1b9d3c
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=3aafc6ab8fa8421b17302478105e807a1e1b9d3c

Author: Rafael Antognolli <rafael.antognolli at intel.com>
Date:   Thu Feb 20 11:02:52 2020 -0800

iris: Apply the flushes when switching pipelines.

Even though the workaround description says:

   "all the listed commands are non-pipelined and hence flush caused due
   to pipeline mode change must not cause performance issues..."

My understanding is that we still need to have the flushes. Also, the
flushes are required not only to stall the pipeline, but also to clear
caches, so I don't think they can simply be discarded.

Additionally, while doing some testing that increased the number of
surface STATE_BASE_ADDRESS emitted, I got a lot more GPU hangs. Adding
these flushes fixes those hangs.

Fixes: b8fbb39a (iris: Implement Gen12 workaround for non pipelined
                 state)

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3908>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3908>
(cherry picked from commit a70a605ad63d95a6e7ce7cfd61fc1ca4e9616e74)

---

 .pick_status.json                     |  2 +-
 src/gallium/drivers/iris/iris_state.c | 16 ++++------------
 2 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/.pick_status.json b/.pick_status.json
index cfb97d06089..0b7e62aa107 100644
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -1156,7 +1156,7 @@
         "description": "iris: Apply the flushes when switching pipelines.",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "master_sha": null,
         "because_sha": "b8fbb39ab2c962e38f6c9d668de57582faf39b70"
     },
diff --git a/src/gallium/drivers/iris/iris_state.c b/src/gallium/drivers/iris/iris_state.c
index 169a5114da2..482b4f68376 100644
--- a/src/gallium/drivers/iris/iris_state.c
+++ b/src/gallium/drivers/iris/iris_state.c
@@ -5047,12 +5047,8 @@ iris_update_surface_base_address(struct iris_batch *batch,
     *  Workaround the non pipelined state not applying in MEDIA/GPGPU pipeline
     *  mode by putting the pipeline temporarily in 3D mode..
     */
-   if (batch->name == IRIS_BATCH_COMPUTE) {
-      iris_emit_cmd(batch, GENX(PIPELINE_SELECT), sel) {
-         sel.MaskBits = 3;
-         sel.PipelineSelection = _3D;
-      }
-   }
+   if (batch->name == IRIS_BATCH_COMPUTE)
+      emit_pipeline_select(batch, _3D);
 #endif
 
    iris_emit_cmd(batch, GENX(STATE_BASE_ADDRESS), sba) {
@@ -5078,12 +5074,8 @@ iris_update_surface_base_address(struct iris_batch *batch,
     *
     *  Put the pipeline back into compute mode.
     */
-   if (batch->name == IRIS_BATCH_COMPUTE) {
-      iris_emit_cmd(batch, GENX(PIPELINE_SELECT), sel) {
-         sel.MaskBits = 3;
-         sel.PipelineSelection = GPGPU;
-      }
-   }
+   if (batch->name == IRIS_BATCH_COMPUTE)
+      emit_pipeline_select(batch, GPGPU);
 #endif
 
    flush_after_state_base_change(batch);