On Fri, Jul 22, 2022 at 02:51:42PM +0200, Andrzej Hajda wrote: > HPD events during driver removal can be generated by hardware and > software frameworks - drm_dp_mst, the former we can avoid by disabling > interrupts, the latter can be triggered by any drm_dp_mst transaction, > and this is too late. Introducing suspended flag allows to solve this > chicken-egg problem. intel_hpd_cancel_work() is always called after suspending MST and disabling IRQs (with the order I suggested in patch 1). If both of these have disabled the corresponding functionality (MST, IRQs) properly with all their MST/IRQ scheduled works guaranteed to not get rescheduled, then it's not clear how could either intel_hpd_trigger_irq() or an IRQ work run. So the problematic sequence would need a better explanation. There's also already dev_priv->runtime_pm.irqs_enabled showing if hotplug interrupts are disabled (along with all other IRQs). > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/5950 > Signed-off-by: Andrzej Hajda <andrzej.hajda@xxxxxxxxx> > Reviewed-by: Arun R Murthy <arun.r.murthy@xxxxxxxxx> > --- > drivers/gpu/drm/i915/display/intel_display.c | 2 +- > drivers/gpu/drm/i915/display/intel_hotplug.c | 11 ++++++++++- > drivers/gpu/drm/i915/display/intel_hotplug.h | 2 +- > drivers/gpu/drm/i915/i915_driver.c | 4 ++-- > drivers/gpu/drm/i915/i915_drv.h | 2 ++ > 5 files changed, 16 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c > index f1c765ac7ab8aa..cd6139bb36151b 100644 > --- a/drivers/gpu/drm/i915/display/intel_display.c > +++ b/drivers/gpu/drm/i915/display/intel_display.c > @@ -9022,7 +9022,7 @@ void intel_modeset_driver_remove_noirq(struct drm_i915_private *i915) > intel_dp_mst_suspend(i915); > > /* MST is the last user of HPD work */ > - intel_hpd_cancel_work(i915); > + intel_hpd_suspend(i915); > > /* poll work can call into fbdev, hence clean that up afterwards */ > intel_fbdev_fini(i915); > diff --git a/drivers/gpu/drm/i915/display/intel_hotplug.c b/drivers/gpu/drm/i915/display/intel_hotplug.c > index 5f8b4f481cff9a..e1d384cb99df6b 100644 > --- a/drivers/gpu/drm/i915/display/intel_hotplug.c > +++ b/drivers/gpu/drm/i915/display/intel_hotplug.c > @@ -303,6 +303,8 @@ static void i915_digport_work_func(struct work_struct *work) > u32 old_bits = 0; > > spin_lock_irq(&dev_priv->irq_lock); > + if (dev_priv->hotplug.suspended) > + return spin_unlock_irq(&dev_priv->irq_lock); > long_port_mask = dev_priv->hotplug.long_port_mask; > dev_priv->hotplug.long_port_mask = 0; > short_port_mask = dev_priv->hotplug.short_port_mask; > @@ -353,6 +355,8 @@ void intel_hpd_trigger_irq(struct intel_digital_port *dig_port) > struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev); > > spin_lock_irq(&i915->irq_lock); > + if (i915->hotplug.suspended) > + return spin_unlock_irq(&i915->irq_lock); > i915->hotplug.short_port_mask |= BIT(dig_port->base.port); > spin_unlock_irq(&i915->irq_lock); > > @@ -475,6 +479,9 @@ void intel_hpd_irq_handler(struct drm_i915_private *dev_priv, > > spin_lock(&dev_priv->irq_lock); > > + if (dev_priv->hotplug.suspended) > + return spin_unlock(&dev_priv->irq_lock); > + > /* > * Determine whether ->hpd_pulse() exists for each pin, and > * whether we have a short or a long pulse. This is needed > @@ -603,6 +610,7 @@ void intel_hpd_init(struct drm_i915_private *dev_priv) > * just to make the assert_spin_locked checks happy. > */ > spin_lock_irq(&dev_priv->irq_lock); > + dev_priv->hotplug.suspended = false; > intel_hpd_irq_setup(dev_priv); > spin_unlock_irq(&dev_priv->irq_lock); > } > @@ -721,13 +729,14 @@ void intel_hpd_init_work(struct drm_i915_private *dev_priv) > intel_hpd_irq_storm_reenable_work); > } > > -void intel_hpd_cancel_work(struct drm_i915_private *dev_priv) > +void intel_hpd_suspend(struct drm_i915_private *dev_priv) > { > if (!HAS_DISPLAY(dev_priv)) > return; > > spin_lock_irq(&dev_priv->irq_lock); > > + dev_priv->hotplug.suspended = true; > dev_priv->hotplug.long_port_mask = 0; > dev_priv->hotplug.short_port_mask = 0; > dev_priv->hotplug.event_bits = 0; > diff --git a/drivers/gpu/drm/i915/display/intel_hotplug.h b/drivers/gpu/drm/i915/display/intel_hotplug.h > index b87e95d606e668..54bddc4dd63421 100644 > --- a/drivers/gpu/drm/i915/display/intel_hotplug.h > +++ b/drivers/gpu/drm/i915/display/intel_hotplug.h > @@ -23,7 +23,7 @@ void intel_hpd_irq_handler(struct drm_i915_private *dev_priv, > void intel_hpd_trigger_irq(struct intel_digital_port *dig_port); > void intel_hpd_init(struct drm_i915_private *dev_priv); > void intel_hpd_init_work(struct drm_i915_private *dev_priv); > -void intel_hpd_cancel_work(struct drm_i915_private *dev_priv); > +void intel_hpd_suspend(struct drm_i915_private *dev_priv); > enum hpd_pin intel_hpd_pin_default(struct drm_i915_private *dev_priv, > enum port port); > bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin); > diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c > index deb8a8b76965a1..57a063a306e3a4 100644 > --- a/drivers/gpu/drm/i915/i915_driver.c > +++ b/drivers/gpu/drm/i915/i915_driver.c > @@ -1092,7 +1092,7 @@ void i915_driver_shutdown(struct drm_i915_private *i915) > intel_dp_mst_suspend(i915); > > intel_runtime_pm_disable_interrupts(i915); > - intel_hpd_cancel_work(i915); > + intel_hpd_suspend(i915); > > intel_suspend_encoders(i915); > intel_shutdown_encoders(i915); > @@ -1161,7 +1161,7 @@ static int i915_drm_suspend(struct drm_device *dev) > intel_dp_mst_suspend(dev_priv); > > intel_runtime_pm_disable_interrupts(dev_priv); > - intel_hpd_cancel_work(dev_priv); > + intel_hpd_suspend(dev_priv); > > intel_suspend_encoders(dev_priv); > > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h > index d25647be25d18b..dc1562b95d7ade 100644 > --- a/drivers/gpu/drm/i915/i915_drv.h > +++ b/drivers/gpu/drm/i915/i915_drv.h > @@ -106,6 +106,8 @@ struct vlv_s0ix_state; > #define HPD_STORM_DEFAULT_THRESHOLD 50 > > struct i915_hotplug { > + bool suspended; > + > struct delayed_work hotplug_work; > > const u32 *hpd, *pch_hpd; > -- > 2.25.1 >
