From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756226Ab2GASWT (ORCPT ); Sun, 1 Jul 2012 14:22:19 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:46999 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755998Ab2GASQk (ORCPT ); Sun, 1 Jul 2012 14:16:40 -0400 Message-Id: <20120701172011.952129862@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Sun, 01 Jul 2012 18:20:43 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Takashi Iwai , Daniel Vetter Subject: [ 37/48] drm/i915: Fix eDP blank screen after S3 resume on HP desktops In-Reply-To: <20120701172006.535271340@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai 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 0ede02a..a748e5c 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);