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            <b><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - [BAT SKL] GPU death starting with first symptom: WARNING backtrace: "DC6 already programmed to be enabled.""
   href="https://bugs.freedesktop.org/show_bug.cgi?id=93768#c2">Comment # 2</a>
              on <a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - [BAT SKL] GPU death starting with first symptom: WARNING backtrace: "DC6 already programmed to be enabled.""
   href="https://bugs.freedesktop.org/show_bug.cgi?id=93768">bug 93768</a>
              from <span class="vcard"><a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> <span class="fn">Chris Wilson</span></a>
</span></b>
        <pre>diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c
b/drivers/gpu/drm/i915/inte
index bbca527..a90d4d0 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -497,7 +497,8 @@ static void gen9_set_dc_state(struct drm_i915_private
*dev_p
        val &= ~mask;
        val |= state;
        I915_WRITE(DC_STATE_EN, val);
-       POSTING_READ(DC_STATE_EN);
+       if (wait_for((I915_READ(DC_STATE_EN) & mask) == state, 500))
+               DRM_ERROR("Timeout whilst enabling DC6\n");
 }

 void bxt_enable_dc9(struct drm_i915_private *dev_priv)</pre>
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