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authorTakashi Iwai <tiwai@suse.de>2012-06-21 15:30:41 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-07-16 08:47:39 -0700
commit9370dd38fdf9c18618efa68cb09daa5bab9885bb (patch)
treec7bc71ed794f220f57be7c6fc1c07cd85f793b7a
parent46f82ddcd34cba5230ddbd914f8e18898ab55355 (diff)
drm/i915: Fix eDP blank screen after S3 resume on HP desktops
commit 6db65cbb941f9d433659bdad02b307f6d94465df upstream. 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 Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-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 bc7dcaa1c68..5ad0b5124b7 100644
--- a/drivers/gpu/drm/i915/i915_suspend.c
+++ b/drivers/gpu/drm/i915/i915_suspend.c
@@ -739,8 +739,11 @@ 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);