From: Imre Deak <imre.deak@intel.com>
Date: Wed, 5 Sep 2018 13:00:05 +0300
Subject: drm/i915/bdw: Increase IPS disable timeout to 100ms
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Git-commit: 92a6803149465e2339f8f7f8f6415d75be80073d
Patch-mainline: v4.19-rc4
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

During IPS disabling the current 42ms timeout value leads to occasional
timeouts, increase it to 100ms which seems to get rid of the problem.

References: https://bugs.freedesktop.org/show_bug.cgi?id=107494
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107562
Reported-by: Diego Viola <diego.viola@gmail.com>
Tested-by: Diego Viola <diego.viola@gmail.com>
Cc: Diego Viola <diego.viola@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180905100005.7663-1-imre.deak@intel.com
(cherry picked from commit acb3ef0ee40ea657280a4a11d9f60eb2937c0dca)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/i915/intel_display.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5079,10 +5079,14 @@ void hsw_disable_ips(const struct intel_
 		mutex_lock(&dev_priv->pcu_lock);
 		WARN_ON(sandybridge_pcode_write(dev_priv, DISPLAY_IPS_CONTROL, 0));
 		mutex_unlock(&dev_priv->pcu_lock);
-		/* wait for pcode to finish disabling IPS, which may take up to 42ms */
+		/*
+		 * Wait for PCODE to finish disabling IPS. The BSpec specified
+		 * 42ms timeout value leads to occasional timeouts so use 100ms
+		 * instead.
+		 */
 		if (intel_wait_for_register(dev_priv,
 					    IPS_CTL, IPS_ENABLE, 0,
-					    42))
+					    100))
 			DRM_ERROR("Timed out waiting for IPS disable\n");
 	} else {
 		I915_WRITE(IPS_CTL, 0);