Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752739Ab3GNQaT (ORCPT ); Sun, 14 Jul 2013 12:30:19 -0400 Received: from mail-lb0-f176.google.com ([209.85.217.176]:62594 "EHLO mail-lb0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752679Ab3GNQaR (ORCPT ); Sun, 14 Jul 2013 12:30:17 -0400 Subject: [PATCH] drm/i915: fix long-standing SNB regression in power consumption after resume To: David Airlie , Daniel Vetter , intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Chris Wilson From: Konstantin Khlebnikov Date: Sun, 14 Jul 2013 20:30:09 +0400 Message-ID: <20130714163009.22374.22100.stgit@zurg> User-Agent: StGit/0.15 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1772 Lines: 44 This patch fixes regression in power consumtion of sandy bridge gpu, which exists since v3.6 Sometimes after resuming from s2ram gpu starts thinking that it's extremely busy. After that it never reaches rc6 state. Bug was introduce by commit b4ae3f22d238617ca11610b29fde16cf8c0bc6e0 ("drm/i915: load boot context at driver init time"). Without documentation it's not clear what is happening here, probably this breaks internal state of hardware ring buffers and confuses RPS engine. Fortunately keeping forcewake during whole initialization sequence in gen6_init_clock_gating() fixes this bug. References: https://bugs.freedesktop.org/show_bug.cgi?id=54089 Signed-off-by: Konstantin Khlebnikov --- drivers/gpu/drm/i915/intel_pm.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index aa01128..839a43f 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -3640,6 +3640,8 @@ static void gen6_init_clock_gating(struct drm_device *dev) int pipe; uint32_t dspclk_gate = ILK_VRHUNIT_CLOCK_GATE_DISABLE; + gen6_gt_force_wake_get(dev_priv); + I915_WRITE(ILK_DSPCLK_GATE_D, dspclk_gate); I915_WRITE(ILK_DISPLAY_CHICKEN2, @@ -3728,6 +3730,8 @@ static void gen6_init_clock_gating(struct drm_device *dev) cpt_init_clock_gating(dev); gen6_check_mch_setup(dev); + + gen6_gt_force_wake_put(dev_priv); } static void gen7_setup_fixed_func_scheduler(struct drm_i915_private *dev_priv) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/