Re: [PATCH v2] drm/i915: Only reprobe display on encoder which has received an HPD event (v2)

From: Jani Nikula <jani.nikula@linux.intel.com>
To: intel-gfx@lists.freedesktop.org
Cc: Egbert Eich <eich@suse.de>, Daniel Vetter <daniel.vetter@intel.com>
Subject: Re: [PATCH v2] drm/i915: Only reprobe display on encoder which has received an HPD event (v2)
Date: Thu, 11 Apr 2013 18:06:23 +0300	[thread overview]
Message-ID: <87obdlcdjk.fsf@intel.com> (raw)
In-Reply-To: <1365688826-13794-1-git-send-email-eich@suse.de>

On Thu, 11 Apr 2013, Egbert Eich <eich@suse.de> wrote:
> Instead of calling into the DRM helper layer to poll all connectors for
> changes in connected displays probe only those connectors which have
> received a hotplug event.
>
> Signed-off-by: Egbert Eich <eich@suse.de>
> Reviewed-by: Jani Nikula <jani.nikula@intel.com>

Yup.

>
> v2: Resolved conflicts with changes in previous commits.
>     Renamed function and and added a WARN_ON() to warn of
>     intel_hpd_irq_event() from being called without
>     mode_config.mutex held - suggested by Jani Nikula.
> ---
>  drivers/gpu/drm/i915/i915_irq.c | 34 ++++++++++++++++++++++++++++------
>  1 file changed, 28 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 6e643d7..54eca33 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -334,6 +334,21 @@ static int i915_get_vblank_timestamp(struct drm_device *dev, int pipe,
>  						     crtc);
>  }
>  
> +static int intel_hpd_irq_event(struct drm_device *dev, struct drm_connector *connector)
> +{
> +	enum drm_connector_status old_status;
> +
> +	WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
> +	old_status = connector->status;
> +
> +	connector->status = connector->funcs->detect(connector, false);
> +	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %d to %d\n",
> +		      connector->base.id,
> +		      drm_get_connector_name(connector),
> +		      old_status, connector->status);
> +	return (old_status != connector->status);
> +}
> +
>  /*
>   * Handle hotplug events outside the interrupt handler proper.
>   */
> @@ -350,6 +365,7 @@ static void i915_hotplug_work_func(struct work_struct *work)
>  	struct drm_connector *connector;
>  	unsigned long irqflags;
>  	bool hpd_disabled = false;
> +	bool changed = false;
>  	u32 hpd_event_bits;
>  
>  	/* HPD irq before everything is fully set up. */
> @@ -395,14 +411,20 @@ static void i915_hotplug_work_func(struct work_struct *work)
>  
>  	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
>  
> -	list_for_each_entry(intel_encoder, &mode_config->encoder_list, base.head)
> -		if (intel_encoder->hot_plug)
> -			intel_encoder->hot_plug(intel_encoder);
> -
> +	list_for_each_entry(connector, &mode_config->connector_list, head) {
> +		intel_connector = to_intel_connector(connector);
> +		intel_encoder = intel_connector->encoder;
> +		if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
> +			if (intel_encoder->hot_plug)
> +				intel_encoder->hot_plug(intel_encoder);
> +			if (intel_hpd_irq_event(dev, connector))
> +				changed = true;
> +		}
> +	}
>  	mutex_unlock(&mode_config->mutex);
>  
> -	/* Just fire off a uevent and let userspace tell us what to do */
> -	drm_helper_hpd_irq_event(dev);
> +	if (changed)
> +		drm_kms_helper_hotplug_event(dev);
>  }
>  
>  static void ironlake_handle_rps_change(struct drm_device *dev)
> -- 
> 1.8.1.4