From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Now that the GGTT PTE updates go straight to GSMBASE (bypassing
GTTMMADR) there should be no more risk of system hangs? So the
"binder" (ie. update the PTEs via MI_UPDATE_GTT) is no longer
necessary, disable it.
My main worry with the MI_UPDATE_GTT are:
- only used on this one platform so very limited testing coverage
- async so more opprtunities to screw things up
- what happens if the engine hangs while we're waiting for MI_UPDATE_GTT
to finish?
- requires working command submission, so even getting a working
display now depends on a lot more extra components working correctly
TODO: MI_UPDATE_GTT might be interesting as an optimization
though, so perhaps someone should look into always using it
(assuming the GPU is alive and well)?
v2: Keep using MI_UPDATE_GTT on VM guests
v3: use i915_direct_stolen_access()
Cc: Paz Zcharya <pazz@xxxxxxxxxxxx>
Cc: Nirmoy Das <nirmoy.das@xxxxxxxxx>
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/gt/intel_gtt.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c b/drivers/gpu/drm/i915/gt/intel_gtt.c
index 86f73fe558ca..7811a8c9da06 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.c
@@ -24,7 +24,8 @@
bool i915_ggtt_require_binder(struct drm_i915_private *i915)
{
/* Wa_13010847436 & Wa_14019519902 */
- return MEDIA_VER_FULL(i915) == IP_VER(13, 0);
+ return !i915_direct_stolen_access(i915) &&
+ MEDIA_VER_FULL(i915) == IP_VER(13, 0);
}
static bool intel_ggtt_update_needs_vtd_wa(struct drm_i915_private *i915)
--
2.43.0
