From: Paulo Zanoni <paulo.r.zanoni at intel.com> So don't read it when capturing the error state. This solves "unclaimed register" messages on Haswell when we have a GPU hang. V2: Check for HAS_PCH_SPLIT instead of Gen5+ because VLV still has this register. Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com> --- drivers/gpu/drm/i915/i915_irq.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index 5fc178e..3c2b05c 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -1387,8 +1387,9 @@ static void i915_capture_error_state(struct drm_device *dev) else if (INTEL_INFO(dev)->gen == 6) error->forcewake = I915_READ(FORCEWAKE); - for_each_pipe(pipe) - error->pipestat[pipe] = I915_READ(PIPESTAT(pipe)); + if (!HAS_PCH_SPLIT(dev)) + for_each_pipe(pipe) + error->pipestat[pipe] = I915_READ(PIPESTAT(pipe)); if (INTEL_INFO(dev)->gen >= 6) { error->error = I915_READ(ERROR_GEN6); -- 1.7.10.4