> Hi Imre, > > > 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.golani@xxxxxxxxx> > > > --- > > > 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. > > > Yes, in case of DG2, after device is suspended, i915_driver_remove is being > called. > Here driver is taking wakeref with disable_rpm_wakeref_asserts when device > was not resumed. > > As per logs, > [ 395.872971] i915 0000:03:00.0: [drm:intel_runtime_suspend [i915]] > Suspending device ... > [ 403.553235] i915_driver_remove: START wakeref=0 [ 403.553288] > i915_driver_remove: before unregister i915 wakeref=65537 (Wakeref Taken) > [ 403.566086] i915 0000:03:00.0: [drm:intel_runtime_resume [i915]] > Resuming device (Later Resuming Device) > > Pushed new change with : > https://patchwork.freedesktop.org/series/107211/#rev5 > Also when compared DG2 logs with ADLP working logs, Already 1 wakeref was taken by DMC firmware(i915/adlp_dmc_ver2_16.bin (v2.16)), in-case of DG2 looks to be missing. To support other targets and to prevent consecutive resuming device added following check, if (i915->runtime_pm.suspended && !atomic_read(&i915->runtime_pm.wakeref_count)) ADLP Logs: --------------- [ 99.502434] i915_driver_probe: START wakeref=0 [ 713.979074] i915 0000:00:02.0: [drm] Finished loading DMC firmware i915/adlp_dmc_ver2_16.bin (v2.16) [ 102.455766] i915_driver_probe: END wakeref=65538 ... [ 103.448570] i915_driver_remove: START wakeref=65537 [ 103.448587] i915_driver_remove: before unregister i915 wakeref=131074 -> (disable_rpm_wakeref_assert) [ 103.585886] i915_driver_remove: END wakeref=0 DG2 Logs: ------------- [ 1271.704314] i915_driver_probe: START wakeref=0 [ 383.050984] i915 0000:03:00.0: [drm] Finished loading DMC firmware i915/dg2_dmc_ver2_07.bin (v2.7) [ 1272.021133] i915_driver_probe: END wakeref=1 ... [ 395.883531] i915 0000:03:00.0: [drm:intel_runtime_suspend [i915]] Device suspended ... [ 1291.450841] i915_driver_remove: START wakeref=0 [ 1291.450877] i915_driver_remove: before unregister i915 wakeref=65537 -> (disable_rpm_wakeref_assert) [ 1291.603281] i915_driver_remove: END wakeref=0 > > > disable_rpm_wakeref_asserts(rpm); > > > > > > intel_opregion_notify_adapter(dev_priv, PCI_D0); > > > -- > > > 2.25.1 > > >
