From 69d1e4c856fd460c37c3eb58996f69dc9add8111 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Thu, 21 Jun 2012 15:30:41 +0200 Subject: [PATCH] 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 Signed-off-by: Daniel Vetter Signed-off-by: Ben Hutchings --- drivers/gpu/drm/i915/i915_suspend.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_suspend.c b/drivers/gpu/drm/i915/i915_suspend.c index a1eb83dc07db..f38d196dda2d 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); -- 2.39.5