From 7dcd2677ea912573d9ed4bcd629b0023b2d11505 Mon Sep 17 00:00:00 2001 From: Konstantin Khlebnikov Date: Wed, 17 Jul 2013 10:22:58 +0400 Subject: [PATCH] drm/i915: fix long-standing SNB regression in power consumption after resume v2 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 exists since kernel v3.6: commit b4ae3f22d238617ca11610b29fde16cf8c0bc6e0 Author: Jesse Barnes Date: Thu Jun 14 11:04:48 2012 -0700 drm/i915: load boot context at driver init time For some reason RC6 is already enabled at the beginning of resuming process. Following initliaztion breaks some internal state and confuses RPS engine. This patch disables RC6 at the beginnig of resume and initialization. I've rearranged initialization sequence, because intel_disable_gt_powersave() needs initialized force_wake_get/put and some locks from the dev_priv. Note: The culprit in the initialization sequence seems to be the write to MBCTL added in the above mentioned commit. The first version of this patch just held a forcewake reference across the clock gating init functions, which seems to have been enought to gather quite a few positive test reports. But since that smelled a bit like ad-hoc duct-tape v2 now just disables rps/rc6 across the entire hw setup. References: https://bugs.freedesktop.org/show_bug.cgi?id=54089 References: https://bugzilla.kernel.org/show_bug.cgi?id=58971 References: https://patchwork.kernel.org/patch/2827634/ (patch v1) Signed-off-by: Konstantin Khlebnikov Cc: Daniel Vetter Cc: Chris Wilson Cc: Jesse Barnes [danvet: Add note about v1 vs. v2 of this patch and use standard layout for the commit citation. Also add the tested-bys from v1 and a cc: stable.] Cc: stable@vger.kernel.org (Note: tiny conflict due to the addition of the backlight lock in 3.11) Tested-by: Alexander Kaltsas (v1) Tested-by: rocko (v1) Tested-by: JohnMB (v1) Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_dma.c | 18 +++++++++--------- drivers/gpu/drm/i915/intel_pm.c | 5 +++-- 2 files changed, 12 insertions(+), 11 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c index adb319b53ecd..5c0663f58aff 100644 --- a/drivers/gpu/drm/i915/i915_dma.c +++ b/drivers/gpu/drm/i915/i915_dma.c @@ -1495,6 +1495,14 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags) dev_priv->dev = dev; dev_priv->info = info; + spin_lock_init(&dev_priv->irq_lock); + spin_lock_init(&dev_priv->gpu_error.lock); + spin_lock_init(&dev_priv->rps.lock); + spin_lock_init(&dev_priv->backlight.lock); + mutex_init(&dev_priv->dpio_lock); + mutex_init(&dev_priv->rps.hw_lock); + mutex_init(&dev_priv->modeset_restore_lock); + i915_dump_device_info(dev_priv); if (i915_get_bridge_dev(dev)) { @@ -1586,6 +1594,7 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags) intel_irq_init(dev); intel_gt_init(dev); + intel_gt_reset(dev); /* Try to make sure MCHBAR is enabled before poking at it */ intel_setup_mchbar(dev); @@ -1610,15 +1619,6 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags) if (!IS_I945G(dev) && !IS_I945GM(dev)) pci_enable_msi(dev->pdev); - spin_lock_init(&dev_priv->irq_lock); - spin_lock_init(&dev_priv->gpu_error.lock); - spin_lock_init(&dev_priv->rps.lock); - spin_lock_init(&dev_priv->backlight.lock); - mutex_init(&dev_priv->dpio_lock); - - mutex_init(&dev_priv->rps.hw_lock); - mutex_init(&dev_priv->modeset_restore_lock); - dev_priv->num_plane = 1; if (IS_VALLEYVIEW(dev)) dev_priv->num_plane = 2; diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index d10e6735771f..828c426b4b92 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -5487,6 +5487,9 @@ void intel_gt_reset(struct drm_device *dev) if (IS_IVYBRIDGE(dev) || IS_HASWELL(dev)) __gen6_gt_force_wake_mt_reset(dev_priv); } + + /* BIOS often leaves RC6 enabled, but disable it for hw init */ + intel_disable_gt_powersave(dev); } void intel_gt_init(struct drm_device *dev) @@ -5495,8 +5498,6 @@ void intel_gt_init(struct drm_device *dev) spin_lock_init(&dev_priv->gt_lock); - intel_gt_reset(dev); - if (IS_VALLEYVIEW(dev)) { dev_priv->gt.force_wake_get = vlv_force_wake_get; dev_priv->gt.force_wake_put = vlv_force_wake_put; -- 2.20.1