From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH] drm/i915: fix long-standing SNB regression in power consumption after resume Date: Tue, 16 Jul 2013 14:06:14 +0200 Message-ID: <20130716120614.GR5784@phenom.ffwll.local> References: <20130714163009.22374.22100.stgit@zurg> <20130716063240.GL5784@phenom.ffwll.local> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20130716063240.GL5784@phenom.ffwll.local> Sender: linux-kernel-owner@vger.kernel.org To: Konstantin Khlebnikov , David Airlie , intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Chris Wilson List-Id: dri-devel@lists.freedesktop.org On Tue, Jul 16, 2013 at 08:32:40AM +0200, Daniel Vetter wrote: > On Sun, Jul 14, 2013 at 08:30:09PM +0400, Konstantin Khlebnikov wrote: > > 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 > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=58971 > Tested-by: Alexander Kaltsas > Tested-by: rocko Tested-by: JohnMB > > > --- > > 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) > > > > -- > Daniel Vetter > Software Engineer, Intel Corporation > +41 (0) 79 365 57 48 - http://blog.ffwll.ch -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch