gbm/dri: Flush after unmap

Drivers may queue dma operations on the context at unmap time so we need
to flush to make sure the data gets to the bo. Ideally the application
would take care of this, but since there appears to be no exported gbm
flush functionality we need to explicitly flush at unmap time.

This fixes a problem where kmscube on vmwgfx in rgba textured mode would
render using an uninitialized texture rather than the intended
rgba pattern.

Signed-off-by: Thomas Hellstrom <[email protected]>
Reviewed-by: Eric Anholt <[email protected]>
(cherry picked from commit ba8df2286a50117011925e915cd832b4a79f126e)

Squashed with commit

gbm/dri: Check dri extension version before flush after unmap

The commit mentioned below required the __DRI2FlushExtension to have
version 4 or above, for GBM functionality. That broke GBM with some
classic dri drivers. Relax that requirement so that we only flush
after unmap if we have version 4 or above. Drivers that require the flush
for correct functionality should implement the desired version.

Fixes: ba8df228 ("gbm/dri: Flush after unmap")
Cc: <[email protected]>
Signed-off-by: Thomas Hellstrom <[email protected]>
Reviewed-by: Emil Velikov <[email protected]>
Tested-by: Dylan Baker <[email protected]>
(cherry picked from commit 18e2aa063ca8e2aeb22a72253891e6f8f5d0d96b)

1 files changed, 8 insertions, 0 deletions

diff --git a/src/gbm/backends/dri/gbm_dri.c b/src/gbm/backends/dri/gbm_dri.c
index 45cb42a8625..decf2030c60 100644
--- a/src/gbm/backends/dri/gbm_dri.c
+++ b/src/gbm/backends/dri/gbm_dri.c
@@ -987,6 +987,14 @@ gbm_dri_bo_unmap(struct gbm_bo *_bo, void *map_data)
       return;
 
    dri->image->unmapImage(dri->context, bo->image, map_data);
+
+   /*
+    * Not all DRI drivers use direct maps. They may queue up DMA operations
+    * on the mapping context. Since there is no explicit gbm flush
+    * mechanism, we need to flush here.
+    */
+   if (dri->flush->base.version >= 4)
+      dri->flush->flush_with_flags(dri->context, NULL, __DRI2_FLUSH_CONTEXT, 0);
 }