According to bspec this workaround helps to reduce lag and improve
performance on edp.
References: HSD#2134579
Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_reg.h | 3 +++
drivers/gpu/drm/i915/intel_pm.c | 8 ++++++++
2 files changed, 11 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index e3077259541a..1f84c2ff3563 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -6035,6 +6035,9 @@ enum skl_disp_power_wells {
#define FORCE_ARB_IDLE_PLANES (1 << 14)
#define SKL_EDP_PSR_FIX_RDWRAP (1 << 3)
+#define CHICKEN_PAR2_1 _MMIO(0x42090)
+#define KVM_CONFIG_CHANGE_NOTIFICATION_SELECT (1 << 14)
+
#define _CHICKEN_PIPESL_1_A 0x420b0
#define _CHICKEN_PIPESL_1_B 0x420b4
#define HSW_FBCQ_DIS (1 << 22)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index fc34add6ab82..5d9b7ff9dc18 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -6870,6 +6870,10 @@ static void skylake_init_clock_gating(struct drm_device *dev)
/* See Bspec note for PSR2_CTL bit 31, Wa#828:skl */
I915_WRITE(CHICKEN_PAR1_1,
I915_READ(CHICKEN_PAR1_1) | SKL_EDP_PSR_FIX_RDWRAP);
+
+ /* WaKVMNotificationOnConfigChange:skl */
+ I915_WRITE(CHICKEN_PAR2_1, I915_READ(CHICKEN_PAR2_1)
+ | KVM_CONFIG_CHANGE_NOTIFICATION_SELECT);
}
static void broadwell_init_clock_gating(struct drm_device *dev)
@@ -6916,6 +6920,10 @@ static void broadwell_init_clock_gating(struct drm_device *dev)
*/
I915_WRITE(HSW_GTT_CACHE_EN, GTT_CACHE_EN_ALL);
+ /* WaKVMNotificationOnConfigChange:bdw */
+ I915_WRITE(CHICKEN_PAR2_1, I915_READ(CHICKEN_PAR2_1)
+ | KVM_CONFIG_CHANGE_NOTIFICATION_SELECT);
+
lpt_init_clock_gating(dev);
}
--
2.5.0
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