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authorTakashi Iwai <tiwai@suse.de>2012-06-21 15:30:41 +0200
committerDaniel Vetter <daniel.vetter@ffwll.ch>2012-06-23 00:01:42 +0200
commit6db65cbb941f9d433659bdad02b307f6d94465df (patch)
treec86ff900f74f8946bdd5cd8d18c9268d4572fc4a
parent58bf8062d0b293b8e1028e5b0342082002886bd4 (diff)
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drm/i915: Fix eDP blank screen after S3 resume on HP desktops
This patch fixes the problem on some HP desktop machines with eDP which give blank screens after S3 resume. It turned out that BLC_PWM_CPU_CTL must be written after BLC_PWM_CPU_CTL2. Otherwise it doesn't take effect on these SNB machines. Tested with 3.5-rc3 kernel. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49233 Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
-rw-r--r--drivers/gpu/drm/i915/i915_suspend.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/i915_suspend.c b/drivers/gpu/drm/i915/i915_suspend.c
index 0ede02a99d91..a748e5cabe14 100644
--- a/drivers/gpu/drm/i915/i915_suspend.c
+++ b/drivers/gpu/drm/i915/i915_suspend.c
@@ -740,8 +740,11 @@ static void i915_restore_display(struct drm_device *dev)
if (HAS_PCH_SPLIT(dev)) {
I915_WRITE(BLC_PWM_PCH_CTL1, dev_priv->saveBLC_PWM_CTL);
I915_WRITE(BLC_PWM_PCH_CTL2, dev_priv->saveBLC_PWM_CTL2);
- I915_WRITE(BLC_PWM_CPU_CTL, dev_priv->saveBLC_CPU_PWM_CTL);
+ /* NOTE: BLC_PWM_CPU_CTL must be written after BLC_PWM_CPU_CTL2;
+ * otherwise we get blank eDP screen after S3 on some machines
+ */
I915_WRITE(BLC_PWM_CPU_CTL2, dev_priv->saveBLC_CPU_PWM_CTL2);
+ I915_WRITE(BLC_PWM_CPU_CTL, dev_priv->saveBLC_CPU_PWM_CTL);
I915_WRITE(PCH_PP_ON_DELAYS, dev_priv->savePP_ON_DELAYS);
I915_WRITE(PCH_PP_OFF_DELAYS, dev_priv->savePP_OFF_DELAYS);
I915_WRITE(PCH_PP_DIVISOR, dev_priv->savePP_DIVISOR);