[Intel-gfx] [PATCH 1/2] drm/i915: Call encoder hotplug for init and resume cases

[Daniel Vetter]

On Wed, Dec 16, 2015 at 04:18:05PM +0530, Sonika Jindal wrote:
> Call the encoders, call the hot_plug if it is registered.
> This is required for connected boot and resume cases to generate
> fake hpd resulting in reading of edid.
> Removing the initial sdvo hot_plug call too so that it will be called
> just once from this loop.
> 
> v2: Schedule a work function to call hot_plug. On CHT, it runs into a
> deadlock if we call ->hot_plug inside hpd_init. This is because, hot_plug
> calls set_edid which tries to acquire the power domain and if power
> well is disabled, we enable power well and call hpd_init again.
> So, schedule a work function from here to call hot_plug and run a
> detect cycle.
> 
> Cc: Shashank Sharma <shashank.sharma at intel.com>
> Signed-off-by: Sonika Jindal <sonika.jindal at intel.com>
> ---
> 
>  drivers/gpu/drm/i915/i915_drv.h      |  1 +
>  drivers/gpu/drm/i915/intel_hotplug.c | 26 ++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_sdvo.c    |  1 -
>  3 files changed, 27 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index bc865e23..4f037b9 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -228,6 +228,7 @@ enum hpd_pin {
>  
>  struct i915_hotplug {
>  	struct work_struct hotplug_work;
> +	struct work_struct edid_work;
>  
>  	struct {
>  		unsigned long last_jiffies;
> diff --git a/drivers/gpu/drm/i915/intel_hotplug.c b/drivers/gpu/drm/i915/intel_hotplug.c
> index b177857..72d8fe8 100644
> --- a/drivers/gpu/drm/i915/intel_hotplug.c
> +++ b/drivers/gpu/drm/i915/intel_hotplug.c
> @@ -442,6 +442,24 @@ void intel_hpd_irq_handler(struct drm_device *dev,
>  		schedule_work(&dev_priv->hotplug.hotplug_work);
>  }
>  
> +static void i915_edid_work_func(struct work_struct *work)
> +{
> +	struct drm_i915_private *dev_priv =
> +		container_of(work, struct drm_i915_private, hotplug.edid_work);
> +	struct drm_device *dev = dev_priv->dev;
> +	struct drm_mode_config *mode_config = &dev->mode_config;
> +	struct intel_encoder *encoder;
> +
> +	mutex_lock(&mode_config->mutex);
> +	list_for_each_entry(encoder, &mode_config->encoder_list,
> +			base.head) {
> +		if (encoder->hot_plug)
> +			encoder->hot_plug(encoder);
> +	}
> +	mutex_unlock(&mode_config->mutex);
> +	drm_helper_hpd_irq_event(dev);
> +}

Why do we need a completely new hand-rolled work? My idea was to reuse the
existing hpd irq handler, but instead of just scheduling that (which won't
do anything) fake-inject a full set of hpd interrupts into it. Well, we
need to inject short-pulse ones to avoid upsetting dp mst.
-Daniel

> +
>  /**
>   * intel_hpd_init - initializes and enables hpd support
>   * @dev_priv: i915 device instance
> @@ -482,12 +500,19 @@ void intel_hpd_init(struct drm_i915_private *dev_priv)
>  	if (dev_priv->display.hpd_irq_setup)
>  		dev_priv->display.hpd_irq_setup(dev);
>  	spin_unlock_irq(&dev_priv->irq_lock);
> +
> +	/*
> +	 * Connected boot / resume scenarios can't generate new hot plug.
> +	 * So, probe it manually.
> +	 */
> +	schedule_work(&dev_priv->hotplug.edid_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.edid_work, i915_edid_work_func);
>  	INIT_DELAYED_WORK(&dev_priv->hotplug.reenable_work,
>  			  intel_hpd_irq_storm_reenable_work);
>  }
> @@ -504,5 +529,6 @@ 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.edid_work);
>  	cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work);
>  }
> diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
> index 06679f1..4238a02 100644
> --- a/drivers/gpu/drm/i915/intel_sdvo.c
> +++ b/drivers/gpu/drm/i915/intel_sdvo.c
> @@ -2466,7 +2466,6 @@ intel_sdvo_dvi_init(struct intel_sdvo *intel_sdvo, int device)
>  		 * Ensure that they get re-enabled when an interrupt happens.
>  		 */
>  		intel_encoder->hot_plug = intel_sdvo_enable_hotplug;
> -		intel_sdvo_enable_hotplug(intel_encoder);
>  	} else {
>  		intel_connector->polled = DRM_CONNECTOR_POLL_CONNECT | DRM_CONNECTOR_POLL_DISCONNECT;
>  	}
> -- 
> 1.9.1
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch