drm/i915/gen9: Check for DC state mismatch
The DMC can incorrectly run off and allow DC states on it's own. We
don't know the root-cause for this yet but this patch makes it more
visible.
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Patrik Jakobsson <patrik.jakobsson@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1455808874-22089-2-git-send-email-mika.kuoppala@intel.com
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index a2e367c..8b9290f 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -494,10 +494,18 @@
val = I915_READ(DC_STATE_EN);
DRM_DEBUG_KMS("Setting DC state from %02x to %02x\n",
val & mask, state);
+
+ /* Check if DMC is ignoring our DC state requests */
+ if ((val & mask) != dev_priv->csr.dc_state)
+ DRM_ERROR("DC state mismatch (0x%x -> 0x%x)\n",
+ dev_priv->csr.dc_state, val & mask);
+
val &= ~mask;
val |= state;
I915_WRITE(DC_STATE_EN, val);
POSTING_READ(DC_STATE_EN);
+
+ dev_priv->csr.dc_state = val & mask;
}
void bxt_enable_dc9(struct drm_i915_private *dev_priv)