On ke, 2015-12-09 at 12:22 +0000, Chris Wilson wrote: > During hangcheck we access the hardware registers, for which we must > hold a runtime pm reference. Hangcheck also should only be running > whilst the GPU is active, and we hold a runtime pm whilst the GPU is > busy. Therefore, if the runtime pm is suspended (no wakelocks held > anywhere) we know the GPU is already idle and we can skip the > hangcheck > (and all further hangchecks until the next request is submitted to > the > GPU, waking it up). > > Currently, hangcheck relies upon being flushed during > intel_runtime_suspend() but is being done so too late causing invalid > hardware access whilst the device is being suspend. By taking an > explicit wakelock (albeit only if already awake) inside hangcheck we > can > remove the synchronous cancellation from the suspend function. > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93121 > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Cc: Imre Deak <imre.deak@xxxxxxxxx> > Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/i915_drv.c | 1 - > drivers/gpu/drm/i915/i915_irq.c | 9 +++++++++ > drivers/gpu/drm/i915/intel_drv.h | 1 + > drivers/gpu/drm/i915/intel_runtime_pm.c | 13 +++++++++++++ > 4 files changed, 23 insertions(+), 1 deletion(-) > <SNIP> > --- a/drivers/gpu/drm/i915/intel_runtime_pm.c > +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c > @@ -2233,6 +2233,19 @@ void intel_runtime_pm_get(struct > drm_i915_private *dev_priv) > WARN(dev_priv->pm.suspended, "Device still suspended.\n"); > } > > +bool intel_runtime_pm_tryget(struct drm_i915_private *dev_priv) > +{ > + /* XXX Ideally we would push this to pm_runtime_tryget() */ I think we first need to have that function upstream, I sent another patch which fixes the same bug in a cleaner manner. This could be incorporated to the series Imre is working on. Regards, Joonas > +#ifdef CONFIG_PM > + if (HAS_RUNTIME_PM(dev_priv)) { > + struct device *device = &dev_priv->dev->pdev->dev; > + return atomic_inc_unless_zero(&dev > ->power.usage_count); > + } > +#else > + return true; > +#endif > +} > + > /** > * intel_runtime_pm_get_noresume - grab a runtime pm reference > * @dev_priv: i915 device instance -- Joonas Lahtinen Open Source Technology Center Intel Corporation _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
