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

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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 4fc688ce79
   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: Tvrtko 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: Chris Wilson <chris@chris-wilson.co.uk>
This commit is contained in:
Tvrtko Ursulin 2016-02-11 10:27:30 +00:00
parent 12c83d9943
commit ee50489877
2 changed files with 4 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/gpu/drm/i915/intel_display.c
View File

@ -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);
}

9
drivers/gpu/drm/i915/intel_pm.c
View File

@ -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;
}