[Intel-gfx] [PATCH] drm/i915: Cancel hangcheck before GPU is suspended

Joonas Lahtinen joonas.lahtinen at linux.intel.com
Wed Dec 9 05:56:13 PST 2015

In order to avoid accessing GPU registers while GPU is suspended cancel
the hangcheck work before calling intel_suspend_complete which actually
puts the GPU to suspend. Otherwise hangcheck might do MMIO reads to a
suspended GPU.

Placement before intel_guc_suspend is imitated from i915_drm_suspend
which cancels the work at i915_gem_suspend, to keep the functions

On VLV systems, namely BYT, this was causing an error during runtime
suspend cycle:

[drm:vlv_check_no_gt_access [i915]] *ERROR* GT register access while GT waking disabled

Testcase: igt/pm_rpm/basic-rte
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93121

Signed-off-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Imre Deak <imre.deak at intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
 drivers/gpu/drm/i915/i915_drv.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index e6935f1..81862d5 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1462,6 +1462,8 @@ static int intel_runtime_suspend(struct device *device)
+	cancel_delayed_work_sync(&dev_priv->gpu_error.hangcheck_work);
@@ -1475,7 +1477,6 @@ static int intel_runtime_suspend(struct device *device)
 		return ret;
-	cancel_delayed_work_sync(&dev_priv->gpu_error.hangcheck_work);
 	intel_uncore_forcewake_reset(dev, false);
 	dev_priv->pm.suspended = true;

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