drm/i915: Fix nesting of rps.mutex and struct_mutex during powersave init
During intel_gt_powersave_init() we take the RPS mutex to ensure that
all locking requirements are met as we talk to the punit, but we also
require the struct_mutex for allocating a slice of the global GTT for a
power context on Valleyview. struct_mutex must be the outer lock here,
as we nest rps.mutex inside later on.
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Fixes: 773ea9a80132 ("drm/i915: Perform static RPS frequency setup before...")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470833904-29886-1-git-send-email-chris@chris-wilson.co.uk
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index aef0b10..f9591b9 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5675,8 +5675,6 @@
u32 pcbr;
int pctx_size = 24*1024;
- mutex_lock(&dev_priv->drm.struct_mutex);
-
pcbr = I915_READ(VLV_PCBR);
if (pcbr) {
/* BIOS set it up already, grab the pre-alloc'd space */
@@ -5712,7 +5710,6 @@
out:
DRM_DEBUG_DRIVER("PCBR: 0x%08x\n", I915_READ(VLV_PCBR));
dev_priv->vlv_pctx = pctx;
- mutex_unlock(&dev_priv->drm.struct_mutex);
}
static void valleyview_cleanup_pctx(struct drm_i915_private *dev_priv)
@@ -6488,6 +6485,7 @@
intel_runtime_pm_get(dev_priv);
}
+ mutex_lock(&dev_priv->drm.struct_mutex);
mutex_lock(&dev_priv->rps.hw_lock);
/* Initialize RPS limits (for userspace) */
@@ -6529,6 +6527,7 @@
dev_priv->rps.boost_freq = dev_priv->rps.max_freq;
mutex_unlock(&dev_priv->rps.hw_lock);
+ mutex_unlock(&dev_priv->drm.struct_mutex);
intel_autoenable_gt_powersave(dev_priv);
}