[PATCH 20/59] drm/i915: Display WA #1185 WaDisableDARBFClkGating:cnl, glk

[Timo Aaltonen]

From: Rodrigo Vivi <rodrigo.vivi at intel.com>

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

Display is not sending a PMRsp when a PMReq is received
at the same time that all planes are turned off.
State machine in the dcprunit is stuck in the WAIT4DONE
state which means that there is no fill_done.

WA: disable arbiter clock gating, set bit [27] of 0x46530

v2: As Ville pointed out, based on the description the issue
    can happen when disabling the planes, similar to
    WaRsPkgCStateDisplayPMReq:hsw
    Also description of the issue was updated on commit
    message to make it more clear that we need this
    earlier.
v3: Restore comment about possibility to system hang
    to where we are sure about it, without speculation. (Ville).
v4: Remove doubled sob. Actually do v3 changes :/

Cc: Radhakrishna Sripada <radhakrishna.sripada at intel.com>
Cc: Imre Deak <imre.deak at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171111000319.5040-1-rodrigo.vivi@intel.com
(cherry picked from commit df49ec8223050d510bd243d85c51139fc101029f)
Signed-off-by: Timo Aaltonen <timo.aaltonen at canonical.com>
---
 drivers/gpu/drm/i915/i915_reg.h      |  1 +
 drivers/gpu/drm/i915/intel_display.c | 27 ++++++++++++++++++---------
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 459e85d003e2..626d2c0fac02 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3816,6 +3816,7 @@ enum {
  * GEN9 clock gating regs
  */
 #define GEN9_CLKGATE_DIS_0		_MMIO(0x46530)
+#define   DARBF_GATING_DIS		(1 << 27)
 #define   PWM2_GATING_DIS		(1 << 14)
 #define   PWM1_GATING_DIS		(1 << 13)
 
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index bd7118c8cb83..dc4a86c5855b 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -15141,6 +15141,23 @@ get_encoder_power_domains(struct drm_i915_private *dev_priv)
 	}
 }
 
+static void intel_early_display_was(struct drm_i915_private *dev_priv)
+{
+	/* Display WA #1185 WaDisableDARBFClkGating:cnl,glk */
+	if (IS_CANNONLAKE(dev_priv) || IS_GEMINILAKE(dev_priv))
+		I915_WRITE(GEN9_CLKGATE_DIS_0, I915_READ(GEN9_CLKGATE_DIS_0) |
+			   DARBF_GATING_DIS);
+
+	if (IS_HASWELL(dev_priv)) {
+		/*
+		 * WaRsPkgCStateDisplayPMReq:hsw
+		 * System hang if this isn't done before disabling all planes!
+		 */
+		I915_WRITE(CHICKEN_PAR1_1,
+			   I915_READ(CHICKEN_PAR1_1) | FORCE_ARB_IDLE_PLANES);
+	}
+}
+
 /* Scan out the current hw modeset state,
  * and sanitizes it to the current state
  */
@@ -15154,15 +15171,7 @@ intel_modeset_setup_hw_state(struct drm_device *dev,
 	struct intel_encoder *encoder;
 	int i;
 
-	if (IS_HASWELL(dev_priv)) {
-		/*
-		 * WaRsPkgCStateDisplayPMReq:hsw
-		 * System hang if this isn't done before disabling all planes!
-		 */
-		I915_WRITE(CHICKEN_PAR1_1,
-			   I915_READ(CHICKEN_PAR1_1) | FORCE_ARB_IDLE_PLANES);
-	}
-
+	intel_early_display_was(dev_priv);
 	intel_modeset_readout_hw_state(dev);
 
 	/* HW state is read out, now we need to sanitize this mess. */
-- 
2.15.1