On Thu, 2024-01-04 at 10:30 +0200, Imre Deak wrote:
> As described in the previous patch, an unexpected connector
> detection/modeset started from the intel_hotplug::hotplug_work can
> happen during the driver init/shutdown sequence. Prevent these by
> disabling the queuing of and flushing all the intel_hotplug work that
> can start them at the beginning of the init/shutdown sequence and
> allow
> the queuing only while the display is in the initialized state.
>
> Other work items - like the intel_connector::modeset_retry_work or
> the
> MST probe works - are still enabled and can start a
> detection/modeset,
> but after the previous patch these will be rejected. Disabling these
> works as well is for a follow-up patchset.
>
> Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
Reviewed-by: Jouni Högander <jouni.hogander@xxxxxxxxx>
> ---
> .../gpu/drm/i915/display/intel_display_core.h | 6 +
> .../drm/i915/display/intel_display_driver.c | 4 +
> drivers/gpu/drm/i915/display/intel_dp.c | 2 +-
> drivers/gpu/drm/i915/display/intel_hotplug.c | 158 +++++++++++++++-
> --
> drivers/gpu/drm/i915/display/intel_hotplug.h | 4 +
> 5 files changed, 154 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_core.h
> b/drivers/gpu/drm/i915/display/intel_display_core.h
> index 0b130ca9e6698..8853a05dc3318 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_core.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_core.h
> @@ -174,6 +174,12 @@ struct intel_hotplug {
> struct work_struct poll_init_work;
> bool poll_enabled;
>
> + /*
> + * Queuing of hotplug_work, reenable_work and poll_init_work
> is
> + * enabled. Protected by drm_i915_private::irq_lock.
> + */
> + bool detection_work_enabled;
> +
> unsigned int hpd_storm_threshold;
> /* Whether or not to count short HPD IRQs in HPD storms */
> u8 hpd_short_storm_enabled;
> diff --git a/drivers/gpu/drm/i915/display/intel_display_driver.c
> b/drivers/gpu/drm/i915/display/intel_display_driver.c
> index b2441ab9822c2..40e4ba942fa3a 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_driver.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_driver.c
> @@ -299,10 +299,14 @@ static void set_display_access(struct
> drm_i915_private *i915,
> void intel_display_driver_enable_user_access(struct drm_i915_private
> *i915)
> {
> set_display_access(i915, true, NULL);
> +
> + intel_hpd_enable_detection_work(i915);
> }
>
> void intel_display_driver_disable_user_access(struct
> drm_i915_private *i915)
> {
> + intel_hpd_disable_detection_work(i915);
> +
> set_display_access(i915, false, current);
> }
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index fed649af8fc85..96ec6f1554c60 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -6026,7 +6026,7 @@ static void intel_dp_oob_hotplug_event(struct
> drm_connector *connector,
> spin_unlock_irq(&i915->irq_lock);
>
> if (need_work)
> - queue_delayed_work(i915->unordered_wq, &i915-
> >display.hotplug.hotplug_work, 0);
> + intel_hpd_schedule_detection(i915);
> }
>
> static const struct drm_connector_funcs intel_dp_connector_funcs = {
> diff --git a/drivers/gpu/drm/i915/display/intel_hotplug.c
> b/drivers/gpu/drm/i915/display/intel_hotplug.c
> index 74513c3d3690b..d9ec349f3c8c3 100644
> --- a/drivers/gpu/drm/i915/display/intel_hotplug.c
> +++ b/drivers/gpu/drm/i915/display/intel_hotplug.c
> @@ -177,6 +177,46 @@ static bool intel_hpd_irq_storm_detect(struct
> drm_i915_private *dev_priv,
> return storm;
> }
>
> +static bool detection_work_enabled(struct drm_i915_private *i915)
> +{
> + lockdep_assert_held(&i915->irq_lock);
> +
> + return i915->display.hotplug.detection_work_enabled;
> +}
> +
> +static bool
> +mod_delayed_detection_work(struct drm_i915_private *i915, struct
> delayed_work *work, int delay)
> +{
> + lockdep_assert_held(&i915->irq_lock);
> +
> + if (!detection_work_enabled(i915))
> + return false;
> +
> + return mod_delayed_work(i915->unordered_wq, work, delay);
> +}
> +
> +static bool
> +queue_delayed_detection_work(struct drm_i915_private *i915, struct
> delayed_work *work, int delay)
> +{
> + lockdep_assert_held(&i915->irq_lock);
> +
> + if (!detection_work_enabled(i915))
> + return false;
> +
> + return queue_delayed_work(i915->unordered_wq, work, delay);
> +}
> +
> +static bool
> +queue_detection_work(struct drm_i915_private *i915, struct
> work_struct *work)
> +{
> + lockdep_assert_held(&i915->irq_lock);
> +
> + if (!detection_work_enabled(i915))
> + return false;
> +
> + return queue_work(i915->unordered_wq, work);
> +}
> +
> static void
> intel_hpd_irq_storm_switch_to_polling(struct drm_i915_private
> *dev_priv)
> {
> @@ -213,9 +253,9 @@ intel_hpd_irq_storm_switch_to_polling(struct
> drm_i915_private *dev_priv)
> /* Enable polling and queue hotplug re-enabling. */
> if (hpd_disabled) {
> drm_kms_helper_poll_reschedule(&dev_priv->drm);
> - mod_delayed_work(dev_priv->unordered_wq,
> - &dev_priv-
> >display.hotplug.reenable_work,
> -
> msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
> + mod_delayed_detection_work(dev_priv,
> + &dev_priv-
> >display.hotplug.reenable_work,
> +
> msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
> }
> }
>
> @@ -348,9 +388,9 @@ static void i915_digport_work_func(struct
> work_struct *work)
> if (old_bits) {
> spin_lock_irq(&dev_priv->irq_lock);
> dev_priv->display.hotplug.event_bits |= old_bits;
> + queue_delayed_detection_work(dev_priv,
> + &dev_priv-
> >display.hotplug.hotplug_work, 0);
> spin_unlock_irq(&dev_priv->irq_lock);
> - queue_delayed_work(dev_priv->unordered_wq,
> - &dev_priv-
> >display.hotplug.hotplug_work, 0);
> }
> }
>
> @@ -467,11 +507,11 @@ static void i915_hotplug_work_func(struct
> work_struct *work)
> if (retry) {
> spin_lock_irq(&dev_priv->irq_lock);
> dev_priv->display.hotplug.retry_bits |= retry;
> - spin_unlock_irq(&dev_priv->irq_lock);
>
> - mod_delayed_work(dev_priv->unordered_wq,
> - &dev_priv-
> >display.hotplug.hotplug_work,
> - msecs_to_jiffies(HPD_RETRY_DELAY));
> + mod_delayed_detection_work(dev_priv,
> + &dev_priv-
> >display.hotplug.hotplug_work,
> +
> msecs_to_jiffies(HPD_RETRY_DELAY));
> + spin_unlock_irq(&dev_priv->irq_lock);
> }
> }
>
> @@ -590,7 +630,6 @@ void intel_hpd_irq_handler(struct
> drm_i915_private *dev_priv,
> */
> if (storm_detected)
> intel_hpd_irq_setup(dev_priv);
> - spin_unlock(&dev_priv->irq_lock);
>
> /*
> * Our hotplug handler can grab modeset locks (by calling
> down into the
> @@ -601,8 +640,10 @@ void intel_hpd_irq_handler(struct
> drm_i915_private *dev_priv,
> if (queue_dig)
> queue_work(dev_priv->display.hotplug.dp_wq,
> &dev_priv->display.hotplug.dig_port_work);
> if (queue_hp)
> - queue_delayed_work(dev_priv->unordered_wq,
> - &dev_priv-
> >display.hotplug.hotplug_work, 0);
> + queue_delayed_detection_work(dev_priv,
> + &dev_priv-
> >display.hotplug.hotplug_work, 0);
> +
> + spin_unlock(&dev_priv->irq_lock);
> }
>
> /**
> @@ -781,8 +822,10 @@ void intel_hpd_poll_enable(struct
> drm_i915_private *dev_priv)
> * As well, there's no issue if we race here since we always
> reschedule
> * this worker anyway
> */
> - queue_work(dev_priv->unordered_wq,
> - &dev_priv->display.hotplug.poll_init_work);
> + spin_lock_irq(&dev_priv->irq_lock);
> + queue_detection_work(dev_priv,
> + &dev_priv-
> >display.hotplug.poll_init_work);
> + spin_unlock_irq(&dev_priv->irq_lock);
> }
>
> /**
> @@ -810,8 +853,11 @@ void intel_hpd_poll_disable(struct
> drm_i915_private *dev_priv)
> return;
>
> WRITE_ONCE(dev_priv->display.hotplug.poll_enabled, false);
> - queue_work(dev_priv->unordered_wq,
> - &dev_priv->display.hotplug.poll_init_work);
> +
> + spin_lock_irq(&dev_priv->irq_lock);
> + queue_detection_work(dev_priv,
> + &dev_priv-
> >display.hotplug.poll_init_work);
> + spin_unlock_irq(&dev_priv->irq_lock);
> }
>
> void intel_hpd_init_early(struct drm_i915_private *i915)
> @@ -833,6 +879,20 @@ void intel_hpd_init_early(struct
> drm_i915_private *i915)
> i915->display.hotplug.hpd_short_storm_enabled =
> !HAS_DP_MST(i915);
> }
>
> +static bool cancel_all_detection_work(struct drm_i915_private *i915)
> +{
> + bool was_pending = false;
> +
> + if (cancel_delayed_work_sync(&i915-
> >display.hotplug.hotplug_work))
> + was_pending = true;
> + if (cancel_work_sync(&i915->display.hotplug.poll_init_work))
> + was_pending = true;
> + if (cancel_delayed_work_sync(&i915-
> >display.hotplug.reenable_work))
> + was_pending = true;
> +
> + return was_pending;
> +}
> +
> void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
> {
> if (!HAS_DISPLAY(dev_priv))
> @@ -848,9 +908,13 @@ void intel_hpd_cancel_work(struct
> drm_i915_private *dev_priv)
> spin_unlock_irq(&dev_priv->irq_lock);
>
> cancel_work_sync(&dev_priv->display.hotplug.dig_port_work);
> - cancel_delayed_work_sync(&dev_priv-
> >display.hotplug.hotplug_work);
> - cancel_work_sync(&dev_priv->display.hotplug.poll_init_work);
> - cancel_delayed_work_sync(&dev_priv-
> >display.hotplug.reenable_work);
> +
> + /*
> + * All other work triggered by hotplug events should be
> canceled by
> + * now.
> + */
> + if (cancel_all_detection_work(dev_priv))
> + drm_dbg_kms(&dev_priv->drm, "Hotplug detection work
> still active\n");
> }
>
> bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum
> hpd_pin pin)
> @@ -880,6 +944,62 @@ void intel_hpd_enable(struct drm_i915_private
> *dev_priv, enum hpd_pin pin)
> spin_unlock_irq(&dev_priv->irq_lock);
> }
>
> +static void queue_work_for_missed_irqs(struct drm_i915_private
> *i915)
> +{
> + bool queue_work = false;
> + enum hpd_pin pin;
> +
> + lockdep_assert_held(&i915->irq_lock);
> +
> + if (i915->display.hotplug.event_bits ||
> + i915->display.hotplug.retry_bits)
> + queue_work = true;
> +
> + for_each_hpd_pin(pin) {
> + switch (i915->display.hotplug.stats[pin].state) {
> + case HPD_MARK_DISABLED:
> + queue_work = true;
> + break;
> + case HPD_ENABLED:
> + break;
> + default:
> + MISSING_CASE(i915-
> >display.hotplug.stats[pin].state);
> + }
> + }
> +
> + if (queue_work)
> + queue_delayed_detection_work(i915, &i915-
> >display.hotplug.hotplug_work, 0);
> +}
> +
> +void intel_hpd_enable_detection_work(struct drm_i915_private *i915)
> +{
> + spin_lock_irq(&i915->irq_lock);
> + i915->display.hotplug.detection_work_enabled = true;
> + queue_work_for_missed_irqs(i915);
> + spin_unlock_irq(&i915->irq_lock);
> +}
> +
> +void intel_hpd_disable_detection_work(struct drm_i915_private *i915)
> +{
> + spin_lock_irq(&i915->irq_lock);
> + i915->display.hotplug.detection_work_enabled = false;
> + spin_unlock_irq(&i915->irq_lock);
> +
> + cancel_all_detection_work(i915);
> +}
> +
> +bool intel_hpd_schedule_detection(struct drm_i915_private *i915)
> +{
> + unsigned long flags;
> + bool ret;
> +
> + spin_lock_irqsave(&i915->irq_lock, flags);
> + ret = queue_delayed_detection_work(i915, &i915-
> >display.hotplug.hotplug_work, 0);
> + spin_unlock_irqrestore(&i915->irq_lock, flags);
> +
> + return ret;
> +}
> +
> static int i915_hpd_storm_ctl_show(struct seq_file *m, void *data)
> {
> struct drm_i915_private *dev_priv = m->private;
> diff --git a/drivers/gpu/drm/i915/display/intel_hotplug.h
> b/drivers/gpu/drm/i915/display/intel_hotplug.h
> index 424ae5dbf5a0e..a17253ddec83a 100644
> --- a/drivers/gpu/drm/i915/display/intel_hotplug.h
> +++ b/drivers/gpu/drm/i915/display/intel_hotplug.h
> @@ -30,4 +30,8 @@ bool intel_hpd_disable(struct drm_i915_private
> *dev_priv, enum hpd_pin pin);
> void intel_hpd_enable(struct drm_i915_private *dev_priv, enum
> hpd_pin pin);
> void intel_hpd_debugfs_register(struct drm_i915_private *i915);
>
> +void intel_hpd_enable_detection_work(struct drm_i915_private *i915);
> +void intel_hpd_disable_detection_work(struct drm_i915_private
> *i915);
> +bool intel_hpd_schedule_detection(struct drm_i915_private *i915);
> +
> #endif /* __INTEL_HOTPLUG_H__ */
