From ee504898777b7d14a6058fc1f1a93d02d974de87 Mon Sep 17 00:00:00 2001 From: Tvrtko Ursulin Date: Thu, 11 Feb 2016 10:27:30 +0000 Subject: [PATCH] drm/i915: Fix struct mutex vs. RPS lock inversion MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit RPS lock must be taken before the struct_mutex to avoid locking inversion. So stop grabbing it for the whole powersave initialization and instead only take it during the sections which need it. Also, struct_mutex is not needed any more since dedicated RPS lock was added in: commit 4fc688ce79772496503d22263d61b071a8fb596e Author: Jesse Barnes Date: Fri Nov 2 11:14:01 2012 -0700 drm/i915: protect RPS/RC6 related accesses (including PCU) with a new mutex Based on prototype patch by Chris Wilson and a subsequent mailing list discussion involving Ville, Imre, Chris and Daniel. v2: More details in the commit. v3: Use drm_gem_object_unreference_unlocked. (Chris Wilson) Signed-off-by: Tvrtko Ursulin Cc: Chris Wilson Cc: Ville Syrjälä Cc: Imre Deak Cc: Daniel Vetter Reviewed-by: Chris Wilson --- drivers/gpu/drm/i915/intel_display.c | 4 ---- drivers/gpu/drm/i915/intel_pm.c | 9 ++++----- 2 files changed, 4 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 0811dd136c56..4d30bca0b26b 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -15971,9 +15971,7 @@ void intel_modeset_gem_init(struct drm_device *dev) struct drm_i915_gem_object *obj; int ret; - mutex_lock(&dev->struct_mutex); intel_init_gt_powersave(dev); - mutex_unlock(&dev->struct_mutex); intel_modeset_init_hw(dev); @@ -16053,9 +16051,7 @@ void intel_modeset_cleanup(struct drm_device *dev) intel_cleanup_overlay(dev); - mutex_lock(&dev->struct_mutex); intel_cleanup_gt_powersave(dev); - mutex_unlock(&dev->struct_mutex); intel_teardown_gmbus(dev); } diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 379eabe093cb..8e869f183404 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -5229,8 +5229,6 @@ static void cherryview_setup_pctx(struct drm_device *dev) u32 pcbr; int pctx_size = 32*1024; - WARN_ON(!mutex_is_locked(&dev->struct_mutex)); - pcbr = I915_READ(VLV_PCBR); if ((pcbr >> VLV_PCBR_ADDR_SHIFT) == 0) { DRM_DEBUG_DRIVER("BIOS didn't set up PCBR, fixing up\n"); @@ -5252,7 +5250,7 @@ static void valleyview_setup_pctx(struct drm_device *dev) u32 pcbr; int pctx_size = 24*1024; - WARN_ON(!mutex_is_locked(&dev->struct_mutex)); + mutex_lock(&dev->struct_mutex); pcbr = I915_READ(VLV_PCBR); if (pcbr) { @@ -5280,7 +5278,7 @@ static void valleyview_setup_pctx(struct drm_device *dev) pctx = i915_gem_object_create_stolen(dev, pctx_size); if (!pctx) { DRM_DEBUG("not enough stolen space for PCTX, disabling\n"); - return; + goto out; } pctx_paddr = dev_priv->mm.stolen_base + pctx->stolen->start; @@ -5289,6 +5287,7 @@ static void valleyview_setup_pctx(struct drm_device *dev) out: DRM_DEBUG_DRIVER("PCBR: 0x%08x\n", I915_READ(VLV_PCBR)); dev_priv->vlv_pctx = pctx; + mutex_unlock(&dev->struct_mutex); } static void valleyview_cleanup_pctx(struct drm_device *dev) @@ -5298,7 +5297,7 @@ static void valleyview_cleanup_pctx(struct drm_device *dev) if (WARN_ON(!dev_priv->vlv_pctx)) return; - drm_gem_object_unreference(&dev_priv->vlv_pctx->base); + drm_gem_object_unreference_unlocked(&dev_priv->vlv_pctx->base); dev_priv->vlv_pctx = NULL; } -- 2.11.0