[PATCH 34/59] drm/i915: Implement WaDisableEarlyEOT.

[Timo Aaltonen]

From: Rafael Antognolli <rafael.antognolli at intel.com>

BugLink: http://bugs.launchpad.net/bugs/1757573

There seems to be another clock gating issue which the workaround is
described as:

   "WA: Set 0xE4F0[1] = 1 to disable Early EOT of thread."

Signed-off-by: Rafael Antognolli <rafael.antognolli at intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi at intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171216001117.14232-2-rafael.antognolli@intel.com
(cherry picked from commit a2b16588578f8edd0e39c7a6554b047b13e8ca79)
Signed-off-by: Timo Aaltonen <timo.aaltonen at canonical.com>
---
 drivers/gpu/drm/i915/i915_reg.h        | 1 +
 drivers/gpu/drm/i915/intel_engine_cs.c | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 283d2adb9122..3863bb278696 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -8111,6 +8111,7 @@ enum {
 #define   PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE	(1<<8)
 #define   STALL_DOP_GATING_DISABLE		(1<<5)
 #define   THROTTLE_12_5				(7<<2)
+#define   DISABLE_EARLY_EOT			(1<<1)
 
 #define GEN7_ROW_CHICKEN2		_MMIO(0xe4f4)
 #define GEN7_ROW_CHICKEN2_GT2		_MMIO(0xf4f4)
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index 6074e04dc99f..8e59c2759cf1 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -1327,6 +1327,9 @@ static int cnl_init_workarounds(struct intel_engine_cs *engine)
 	if (ret)
 		return ret;
 
+	/* WaDisableEarlyEOT:cnl */
+	WA_SET_BIT_MASKED(GEN8_ROW_CHICKEN, DISABLE_EARLY_EOT);
+
 	return 0;
 }
 
-- 
2.15.1