Commit ee504898 authored by Tvrtko Ursulin's avatar Tvrtko Ursulin
Browse files

drm/i915: Fix struct mutex vs. RPS lock inversion 



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 4fc688ce
   Author: Jesse Barnes <jbarnes@virtuousgeek.org>
   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: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
parent 12c83d99

drivers/gpu/drm/i915/intel_display.c

+0 −4
Original line number Diff line number Diff line
@@ -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);

}

drivers/gpu/drm/i915/intel_pm.c

+4 −5
Original line number Diff line number Diff line
@@ -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;

}

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