As a forewarning: I have confirmed the CRT hpd loops Vsyrjala has mentioned, and
they are triggered by this patch. I'm working on a patch for this atm.
On Mon, 2016-06-20 at 16:57 -0400, Lyude wrote:
> Unfortunately, there's two situations where we lose hpd right now:
> - Runtime suspend
> - When we've shut off all of the power wells on Valleyview/Cherryview
>
> While it would be nice if this didn't cause issues, this has the
> ability to get us in some awkward states where a user won't be able to
> get their display to turn on. For instance; if we boot a Valleyview
> system without any monitors connected, it won't need any of it's power
> wells and thus shut them off. Since this causes us to lose HPD, this
> means that unless the user knows how to ssh into their machine and do a
> manual reprobe for monitors, none of the monitors they connect after
> booting will actually work.
>
> Eventually we should come up with a better fix then having to enable
> polling for this, since this makes rpm a lot less useful, but for now
> the infrastructure in i915 just isn't there yet to get hpd in these
> situations.
>
> Changes since v1:
> - Add comment explaining the addition of the if
> (!mode_config->poll_running) in intel_hpd_init()
> - Remove unneeded if (!dev->mode_config.poll_enabled) in
> i915_hpd_poll_init_work()
> - Call to drm_helper_hpd_irq_event() after we disable polling
> - Add cancel_work_sync() call to intel_hpd_cancel_work()
>
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Acked-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> Signed-off-by: Lyude <cpaul@xxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_drv.c | 7 ++-
> drivers/gpu/drm/i915/i915_drv.h | 3 ++
> drivers/gpu/drm/i915/intel_drv.h | 2 +
> drivers/gpu/drm/i915/intel_hotplug.c | 82 +++++++++++++++++++++++++++++---
> -
> drivers/gpu/drm/i915/intel_runtime_pm.c | 3 ++
> 5 files changed, 86 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 3eb47fb..5381d9e 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1612,6 +1612,9 @@ static int intel_runtime_suspend(struct device *device)
>
> assert_forcewakes_inactive(dev_priv);
>
> + if (!IS_VALLEYVIEW(dev_priv) || !IS_CHERRYVIEW(dev_priv))
> + intel_hpd_poll_enable(dev_priv, true);
> +
> DRM_DEBUG_KMS("Device suspended\n");
> return 0;
> }
> @@ -1667,8 +1670,10 @@ static int intel_runtime_resume(struct device *device)
> * power well, so hpd is reinitialized from there. For
> * everyone else do it here.
> */
> - if (!IS_VALLEYVIEW(dev_priv) && !IS_CHERRYVIEW(dev_priv))
> + if (!IS_VALLEYVIEW(dev_priv) && !IS_CHERRYVIEW(dev_priv)) {
> intel_hpd_init(dev_priv);
> + intel_hpd_poll_enable(dev_priv, false);
> + }
>
> intel_enable_gt_powersave(dev_priv);
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 1eef5ef..6f7075d 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -283,6 +283,9 @@ struct i915_hotplug {
> u32 short_port_mask;
> struct work_struct dig_port_work;
>
> + struct work_struct poll_enable_work;
> + bool poll_enabled;
> +
> /*
> * if we get a HPD irq from DP and a HPD irq from non-DP
> * the non-DP HPD could block the workqueue on a mode config
> diff --git a/drivers/gpu/drm/i915/intel_drv.h
> b/drivers/gpu/drm/i915/intel_drv.h
> index cd14751..87c5143 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1384,6 +1384,8 @@ int intel_dsi_dcs_init_backlight_funcs(struct
> intel_connector *intel_connector);
>
> /* intel_dvo.c */
> void intel_dvo_init(struct drm_device *dev);
> +/* intel_hotplug.c */
> +void intel_hpd_poll_enable(struct drm_i915_private *dev_priv, bool enabled);
>
>
> /* legacy fbdev emulation in intel_fbdev.c */
> diff --git a/drivers/gpu/drm/i915/intel_hotplug.c
> b/drivers/gpu/drm/i915/intel_hotplug.c
> index ec3285f..3ef5096 100644
> --- a/drivers/gpu/drm/i915/intel_hotplug.c
> +++ b/drivers/gpu/drm/i915/intel_hotplug.c
> @@ -464,20 +464,34 @@ void intel_hpd_init(struct drm_i915_private *dev_priv)
> dev_priv->hotplug.stats[i].count = 0;
> dev_priv->hotplug.stats[i].state = HPD_ENABLED;
> }
> - list_for_each_entry(connector, &mode_config->connector_list, head) {
> - struct intel_connector *intel_connector =
> to_intel_connector(connector);
> - connector->polled = intel_connector->polled;
>
> - /* MST has a dynamic intel_connector->encoder and it's
> reprobing
> - * is all handled by the MST helpers. */
> - if (intel_connector->mst_port)
> - continue;
> + /*
> + * When we're in the midst of doing connector polling in situations
> + * where we don't have working hpd, we need to make sure we don't try
> + * changing the polling settings of any connectors, since this can
> lead
> + * to us setting connector->polled to DRM_CONNECTOR_POLL_HPD,
> resulting
> + * in DRM's polling helpers automatically skipping the rest of the
> + * connectors that still need polling
> + */
> + if (!mode_config->poll_running) {
> + list_for_each_entry(connector, &mode_config->connector_list,
> head) {
> + struct intel_connector *intel_connector =
> + to_intel_connector(connector);
> + connector->polled = intel_connector->polled;
>
> - if (!connector->polled && I915_HAS_HOTPLUG(dev) &&
> - intel_connector->encoder->hpd_pin > HPD_NONE)
> - connector->polled = DRM_CONNECTOR_POLL_HPD;
> + /* MST has a dynamic intel_connector->encoder and
> it's
> + * reprobing is all handled by the MST helpers. */
> + if (intel_connector->mst_port)
> + continue;
> +
> + if (!connector->polled && I915_HAS_HOTPLUG(dev) &&
> + intel_connector->encoder->hpd_pin > HPD_NONE)
> + connector->polled = DRM_CONNECTOR_POLL_HPD;
> + }
> }
>
> + intel_hpd_poll_enable(dev_priv, false);
> +
> /*
> * Interrupt setup is already guaranteed to be single-threaded, this
> is
> * just to make the assert_spin_locked checks happy.
> @@ -488,10 +502,57 @@ void intel_hpd_init(struct drm_i915_private *dev_priv)
> spin_unlock_irq(&dev_priv->irq_lock);
> }
>
> +void i915_hpd_poll_init_work(struct work_struct *work) {
> + struct drm_i915_private *dev_priv =
> + container_of(work, struct drm_i915_private,
> + hotplug.poll_enable_work);
> + struct drm_device *dev = dev_priv->dev;
> + struct intel_connector *intel_connector;
> +
> + mutex_lock(&dev->mode_config.mutex);
> +
> + for_each_intel_connector(dev, intel_connector) {
> + struct drm_connector *connector = &intel_connector->base;
> +
> + if (dev_priv->hotplug.poll_enabled) {
> + connector->polled = DRM_CONNECTOR_POLL_CONNECT |
> + DRM_CONNECTOR_POLL_DISCONNECT;
> +
> + } else if (!intel_connector->polled && I915_HAS_HOTPLUG(dev)
> &&
> + intel_connector->encoder->hpd_pin > HPD_NONE) {
> + connector->polled = DRM_CONNECTOR_POLL_HPD;
> + }
> + }
> +
> + if (dev_priv->hotplug.poll_enabled)
> + drm_kms_helper_poll_enable_locked(dev);
> +
> + mutex_unlock(&dev->mode_config.mutex);
> +
> + /*
> + * We might have missed any hotplugs that happened while we were
> + * in the middle of disabling polling
> + */
> + if (!dev_priv->hotplug.poll_enabled)
> + drm_helper_hpd_irq_event(dev);
> +}
> +
> +void intel_hpd_poll_enable(struct drm_i915_private *dev_priv, bool enabled)
> +{
> + dev_priv->hotplug.poll_enabled = enabled;
> +
> + /*
> + * We might already be holding dev->mode_config.mutex, so do this in
> a
> + * seperate worker
> + */
> + schedule_work(&dev_priv->hotplug.poll_enable_work);
> +}
> +
> void intel_hpd_init_work(struct drm_i915_private *dev_priv)
> {
> INIT_WORK(&dev_priv->hotplug.hotplug_work, i915_hotplug_work_func);
> INIT_WORK(&dev_priv->hotplug.dig_port_work, i915_digport_work_func);
> + INIT_WORK(&dev_priv->hotplug.poll_enable_work,
> i915_hpd_poll_init_work);
> INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,
> intel_hpd_irq_storm_reenable_work);
> }
> @@ -508,6 +569,7 @@ void intel_hpd_cancel_work(struct drm_i915_private
> *dev_priv)
>
> cancel_work_sync(&dev_priv->hotplug.dig_port_work);
> cancel_work_sync(&dev_priv->hotplug.hotplug_work);
> + cancel_work_sync(&dev_priv->hotplug.poll_enable_work);
> cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
> }
>
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c
> b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index 6f3d019..592cb7d 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -1099,6 +1099,7 @@ static void vlv_display_power_well_init(struct
> drm_i915_private *dev_priv)
> if (dev_priv->power_domains.initializing)
> return;
>
> + intel_hpd_poll_enable(dev_priv, false);
> intel_hpd_init(dev_priv);
>
> /* Re-enable the ADPA, if we have one */
> @@ -1120,6 +1121,8 @@ static void vlv_display_power_well_deinit(struct
> drm_i915_private *dev_priv)
> synchronize_irq(dev_priv->dev->irq);
>
> vlv_power_sequencer_reset(dev_priv);
> +
> + intel_hpd_poll_enable(dev_priv, true);
> }
>
> static void vlv_display_power_well_enable(struct drm_i915_private *dev_priv,
--
Cheers,
Lyude
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