iris: drop cache coherent cpu mapping for external BO

We have to assume any external buffer could be used by the display HW.
In the case that buffer is also CPU mapped, we want to assume no cache
coherency as it is only available between GT & CPU, not display.

Many thanks to Michel Dänzer for the hint!

v2: Move cache coherent drop to bufmgr (Chris)

v3: Also make BO external if created with PIPE_BIND_SHARED (Eric)

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: <mesa-stable@lists.freedesktop.org>
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/2552
Reviewed-by: Eric Anholt <eric@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4533>

diff --git a/src/gallium/drivers/iris/iris_bufmgr.c b/src/gallium/drivers/iris/iris_bufmgr.c
index ca8db31aed3dafeedcacfe4da76e09f30e039530..c333f7bdaee14e89f46e2bc26ab35fd2bf1c4620 100644 (file)
--- a/src/gallium/drivers/iris/iris_bufmgr.c
+++ b/src/gallium/drivers/iris/iris_bufmgr.c
@@ -1376,12 +1376,17 @@ iris_bo_make_external_locked(struct iris_bo *bo)
 {
    if (!bo->external) {
       _mesa_hash_table_insert(bo->bufmgr->handle_table, &bo->gem_handle, bo);
+      /* If a BO is going to be used externally, it could be sent to the
+       * display HW. So make sure our CPU mappings don't assume cache
+       * coherency since display is outside that cache.
+       */
+      bo->cache_coherent = false;
       bo->external = true;
       bo->reusable = false;
    }
 }
 
-static void
+void
 iris_bo_make_external(struct iris_bo *bo)
 {
    struct iris_bufmgr *bufmgr = bo->bufmgr;

diff --git a/src/gallium/drivers/iris/iris_bufmgr.h b/src/gallium/drivers/iris/iris_bufmgr.h
index caeba61a650ba670a831370f42d4537a682cdf4b..6f4bcbf5e567a8d0daf52f4649ba29cb3e295afd 100644 (file)
--- a/src/gallium/drivers/iris/iris_bufmgr.h
+++ b/src/gallium/drivers/iris/iris_bufmgr.h
@@ -309,6 +309,13 @@ int iris_bo_get_tiling(struct iris_bo *bo, uint32_t *tiling_mode,
  */
 int iris_bo_flink(struct iris_bo *bo, uint32_t *name);
 
+/**
+ * Make a BO externally accessible.
+ *
+ * \param bo Buffer to make external
+ */
+void iris_bo_make_external(struct iris_bo *bo);
+
 /**
  * Returns 1 if mapping the buffer for write could cause the process
  * to block, due to the object being active in the GPU.

diff --git a/src/gallium/drivers/iris/iris_resource.c b/src/gallium/drivers/iris/iris_resource.c
index 40655bb4032ba5e4990b36c5dc9e520ab26a267d..3476809529d0b2cc7933e4d736b81186b407a834 100644 (file)
--- a/src/gallium/drivers/iris/iris_resource.c
+++ b/src/gallium/drivers/iris/iris_resource.c
@@ -801,6 +801,9 @@ iris_resource_create_for_buffer(struct pipe_screen *pscreen,
       return NULL;
    }
 
+   if (templ->bind & PIPE_BIND_SHARED)
+      iris_bo_make_external(res->bo);
+
    return &res->base;
 }
 
@@ -924,6 +927,9 @@ iris_resource_create_with_modifiers(struct pipe_screen *pscreen,
       map_aux_addresses(screen, res);
    }
 
+   if (templ->bind & PIPE_BIND_SHARED)
+      iris_bo_make_external(res->bo);
+
    return &res->base;
 
 fail: