gem_workarounds reports that the SLICE_UNIT_LEVEL_CLKGATE write isn't
sticking. Commit 0a60797a0efb ("drm/i915: Implement
ReadHitWriteOnlyDisable.") presumes that SLICE_UNIT_LEVEL_CLKGATE is a
masked register in the context image, but commit 90007bca6162
("drm/i915/cnl: Introduce initial Cannonlake Workarounds.") lists it as
an ordering unmasked register. The masked write will be losing the
default settings if we trust the original commit. That gem_workarounds
reports the value is lost entirely is more worrying though -- but it
clearly suggests that it is not a masked register in the context image,
so unify both w/a to use the original rmw.
Fixes: 0a60797a0efb ("drm/i915: Implement ReadHitWriteOnlyDisable.")
References: 90007bca6162 ("drm/i915/cnl: Introduce initial Cannonlake Workarounds.")
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Rafael Antognolli <rafael.antognolli@xxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Cc: Oscar Mateo <oscar.mateo@xxxxxxxxx>
Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_engine_cs.c | 3 ---
drivers/gpu/drm/i915/intel_pm.c | 8 +++++---
2 files changed, 5 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index 23694916662f..125e4d90c5f7 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -1324,9 +1324,6 @@ static int cnl_init_workarounds(struct intel_engine_cs *engine)
WA_SET_FIELD_MASKED(GEN8_CS_CHICKEN1, GEN9_PREEMPT_GPGPU_LEVEL_MASK,
GEN9_PREEMPT_GPGPU_COMMAND_LEVEL);
- /* ReadHitWriteOnlyDisable: cnl */
- WA_SET_BIT_MASKED(SLICE_UNIT_LEVEL_CLKGATE, RCCUNIT_CLKGATE_DIS);
-
/* WaEnablePreemptionGranularityControlByUMD:cnl */
I915_WRITE(GEN7_FF_SLICE_CS_CHICKEN1,
_MASKED_BIT_ENABLE(GEN9_FFSC_PERCTX_PREEMPT_CTRL));
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index c1a56809f143..6dee6b15f726 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -8474,11 +8474,13 @@ static void cnl_init_clock_gating(struct drm_i915_private *dev_priv)
I915_WRITE(DISP_ARB_CTL, I915_READ(DISP_ARB_CTL) |
DISP_FBC_MEMORY_WAKE);
+ val = I915_READ(SLICE_UNIT_LEVEL_CLKGATE);
+ /* ReadHitWriteOnlyDisable:cnl */
+ val |= RCCUNIT_CLKGATE_DIS;
/* WaSarbUnitClockGatingDisable:cnl (pre-prod) */
if (IS_CNL_REVID(dev_priv, CNL_REVID_A0, CNL_REVID_B0))
- I915_WRITE(SLICE_UNIT_LEVEL_CLKGATE,
- I915_READ(SLICE_UNIT_LEVEL_CLKGATE) |
- SARBUNIT_CLKGATE_DIS);
+ val |= SARBUNIT_CLKGATE_DIS;
+ I915_WRITE(SLICE_UNIT_LEVEL_CLKGATE, val);
/* Display WA #1133: WaFbcSkipSegments:cnl */
val = I915_READ(ILK_DPFC_CHICKEN);
--
2.15.0
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