From a8ab5ed5e1bf856eceaab5579236de6f92822b9f Mon Sep 17 00:00:00 2001
From: Tim Gore <tim.gore@intel.com>
Date: Mon, 13 Jun 2016 12:15:01 +0100
Subject: [PATCH] drm/i915/gen9: implement
WaConextSwitchWithConcurrentTLBInvalidate
This patch enables a workaround for a mid thread preemption
issue where a hardware timing problem can prevent the
context restore from happening, leading to a hang.
v2: move to gen9_init_workarounds (Arun)
v3: move to start of gen9_init_workarounds (Arun)
Signed-off-by: Tim Gore <tim.gore@intel.com>
Reviewed-by: Arun Siluvery <arun.siluvery@linux.intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1465816501-25557-1-git-send-email-tim.gore@intel.com
---
drivers/gpu/drm/i915/i915_reg.h | 4 ++++
drivers/gpu/drm/i915/intel_ringbuffer.c | 3 +++
2 files changed, 7 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 9d7979b2e5df..4657aed5d7b0 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1810,6 +1810,10 @@ enum skl_disp_power_wells {
#define GEN9_IZ_HASHING_MASK(slice) (0x3 << ((slice) * 2))
#define GEN9_IZ_HASHING(slice, val) ((val) << ((slice) * 2))
+/* chicken reg for WaConextSwitchWithConcurrentTLBInvalidate */
+#define GEN9_CSFE_CHICKEN1_RCS _MMIO(0x20D4)
+#define GEN9_PREEMPT_GPGPU_SYNC_SWITCH_DISABLE (1 << 2)
+
/* WaClearTdlStateAckDirtyBits */
#define GEN8_STATE_ACK _MMIO(0x20F0)
#define GEN9_STATE_ACK_SLICE1 _MMIO(0x20F8)
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index cf8d0bf29a97..110c7fc957b7 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -910,6 +910,9 @@ static int gen9_init_workarounds(struct intel_engine_cs *engine)
struct drm_i915_private *dev_priv = engine->i915;
int ret;
+ /* WaConextSwitchWithConcurrentTLBInvalidate:skl,bxt,kbl */
+ I915_WRITE(GEN9_CSFE_CHICKEN1_RCS, _MASKED_BIT_ENABLE(GEN9_PREEMPT_GPGPU_SYNC_SWITCH_DISABLE));
+
/* WaEnableLbsSlaRetryTimerDecrement:skl,bxt,kbl */
I915_WRITE(BDW_SCRATCH1, I915_READ(BDW_SCRATCH1) |
GEN9_LBS_SLA_RETRY_TIMER_DECREMENT_ENABLE);
--
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