On Fri, Aug 12, 2022 at 10:17:24AM +0530, Mitul Golani wrote: > While executing i915_selftest, wakeref imbalance warning is seen > with i915_selftest failure. > > When device is already suspended, wakeref is acquired by > disable_rpm_wakeref_asserts and rpm ownership is transferred back > to core. During this case wakeref_count will not be zero. > Once driver is unregistered, this wakeref is released with > enable_rpm_wakeref_asserts and balancing wakeref_count acquired > by driver. > > This patch will fix the warning callstack by adding check if device > is already suspended and rpm ownership transfer is going on. > > Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.gol...@intel.com> > --- > drivers/gpu/drm/i915/i915_driver.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/i915_driver.c > b/drivers/gpu/drm/i915/i915_driver.c > index deb8a8b76965..6530a8680cfd 100644 > --- a/drivers/gpu/drm/i915/i915_driver.c > +++ b/drivers/gpu/drm/i915/i915_driver.c > @@ -1670,7 +1670,13 @@ static int intel_runtime_resume(struct device *kdev) > > drm_dbg(&dev_priv->drm, "Resuming device\n"); > > - drm_WARN_ON_ONCE(&dev_priv->drm, atomic_read(&rpm->wakeref_count)); > + /* > + * When device is already suspended, Wakeref is acquired by > disable_rpm_wakeref_asserts > + * and rpm ownership is transferred back to core. During this case > wakeref_count will > + * not be zero. Once driver is unregistered, this wakeref is released > with > + * enable_rpm_wakeref_asserts and balancing wakeref_count acquired by > driver. > + */ > + drm_WARN_ON_ONCE(&dev_priv->drm, atomic_read(&rpm->wakeref_count) && > !rpm->suspended);
I can't see how disable/enable_rpm_wakeref_asserts() can lead to this WARN. They are always called in pairs both in intel_runtime_suspend() and intel_runtime_resume(), leaving rpm->wakeref_count unchanged. The root cause is probably somewhere else, incrementing rpm->wakeref_count without runtime resuming the device. The WARN() condition is corret, we shouldn't get here with a non-zero wakeref_count. rpm->suspended - set in intel_runtime_suspend() and cleared in intel_runtime_resume() - should be always false here, so the above change would just disable the WARN in all cases. > disable_rpm_wakeref_asserts(rpm); > > intel_opregion_notify_adapter(dev_priv, PCI_D0); > -- > 2.25.1 >
