Ensure that any buffer allocated for a scanout image is kept out of the
CPU/LLC cache so as to avoid any visual glitch.
Cc: Kenneth Graunke <kenn...@whitecape.org>
---
src/mesa/drivers/dri/i965/intel_screen.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/src/mesa/drivers/dri/i965/intel_screen.c
b/src/mesa/drivers/dri/i965/intel_screen.c
index 3666b65bb6..3e72ab14c8 100644
--- a/src/mesa/drivers/dri/i965/intel_screen.c
+++ b/src/mesa/drivers/dri/i965/intel_screen.c
@@ -693,6 +693,16 @@ intel_create_image_common(__DRIscreen *dri_screen,
image->pitch = surf.row_pitch;
image->modifier = modifier;
+ /* When a buffer is transformed into a framebuffer and mapped for use
+ * by scanout (i.e. any sprite plane, scanout, cursor, overlay etc),
+ * it is moved to UC - reads by the display engine are serviced directly
+ * from memory ignoring the CPU/LLC cache. If we leave pixels in the CPU
+ * cache due to mistaken use of WB, that causes screen corruption that
+ * randomly heals over time (due to eventual cache eviction).
+ */
+ if (use & (__DRI_IMAGE_USE_CURSOR | __DRI_IMAGE_USE_SCANOUT))
+ image->bo->cache_coherent = false;
+
return image;
}
--
2.13.3
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