On Thu, Jan 25, 2024 at 12:27:36PM +0200, Ville Syrjala wrote: > 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> Hi Ville, Thank you so much for this incredible series. It solves the issue regarding MTL initial plane readout that Andrzej Hajda and I worked on in https://patchwork.freedesktop.org/patch/570811/?series=127130&rev=2 In addition, it solved the issue with the new GOP. I tested it on two different devices with Meteor Lake and it worked perfectly: no i915 errors, no flickers or observable issues. Tested-by: Paz Zcharya <pazz@xxxxxxxxxxxx> > --- > 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 >
