Re: [PATCH v.2 10/12] DRM/i915: Add Reenable Timer to turn Hotplug Detection back on (v2).

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Mar 05, 2013 at 02:48:49AM -0500, Egbert Eich wrote:
> We disable hoptplug detection when we encounter a hotplug event
> storm. Still hotplug detection is required on some outputs (like
> Display Port). The interrupt storm may be only temporary (on certain
> Dell Laptops for instance it happens at certain charging states of
> the system). Thus we enable it after a certain grace period (2 minutes).
> Should the interrupt storm persist it will be detected immediately
> and it will be disabled again.
> 
> v2: Reordered drm_i915_private: moved hotplug_reenable_timer to hpd state tracker.
> 
> Signed-off-by: Egbert Eich <eich@suse.de>
> ---
>  drivers/gpu/drm/i915/i915_drv.h |    2 +
>  drivers/gpu/drm/i915/i915_irq.c |   53 ++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 54 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 296278f..1fb7c44 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -933,6 +933,8 @@ typedef struct drm_i915_private {
>  			HPD_MARK_DISABLED = 2
>  		} hpd_mark;
>  	} hpd_stats[HPD_NUM_PINS];
> +#define I915_REENABLE_HOTPLUG_DELAY (2*60*1000)
> +	struct timer_list hotplug_reenable_timer;
>  
>  	int num_pipe;
>  	int num_pch_pll;
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index d11534c..c688b27 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -367,8 +367,11 @@ static void i915_hotplug_work_func(struct work_struct *work)
>  			connector_disabled = true;
>  		}
>  	}
> -	if (connector_disabled)
> +	if (connector_disabled) {
>  		drm_kms_helper_poll_enable(dev); /* if there were no outputs to poll, poll is disabled */
> +		mod_timer(&dev_priv->hotplug_reenable_timer,
> +			  jiffies + msecs_to_jiffies(I915_REENABLE_HOTPLUG_DELAY));
> +	}
>  
>  	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
>  
> @@ -2244,6 +2247,8 @@ static void valleyview_irq_uninstall(struct drm_device *dev)
>  	if (!dev_priv)
>  		return;
>  
> +	del_timer_sync(&dev_priv->hotplug_reenable_timer);
> +
>  	for_each_pipe(pipe)
>  		I915_WRITE(PIPESTAT(pipe), 0xffff);
>  
> @@ -2265,6 +2270,8 @@ static void ironlake_irq_uninstall(struct drm_device *dev)
>  	if (!dev_priv)
>  		return;
>  
> +	del_timer_sync(&dev_priv->hotplug_reenable_timer);
> +
>  	I915_WRITE(HWSTAM, 0xffffffff);
>  
>  	I915_WRITE(DEIMR, 0xffffffff);
> @@ -2603,6 +2610,8 @@ static void i915_irq_uninstall(struct drm_device * dev)
>  	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
>  	int pipe;
>  
> +	del_timer_sync(&dev_priv->hotplug_reenable_timer);
> +
>  	if (I915_HAS_HOTPLUG(dev)) {
>  		I915_WRITE(PORT_HOTPLUG_EN, 0);
>  		I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
> @@ -2851,6 +2860,8 @@ static void i965_irq_uninstall(struct drm_device * dev)
>  	if (!dev_priv)
>  		return;
>  
> +	del_timer_sync(&dev_priv->hotplug_reenable_timer);
> +
>  	I915_WRITE(PORT_HOTPLUG_EN, 0);
>  	I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
>  
> @@ -2866,6 +2877,44 @@ static void i965_irq_uninstall(struct drm_device * dev)
>  	I915_WRITE(IIR, I915_READ(IIR));
>  }
>  
> +static void i915_reenable_hotplug_timer_func(unsigned long data)
> +{
> +	drm_i915_private_t *dev_priv = (drm_i915_private_t *)data;
> +	struct drm_device *dev = dev_priv->dev;
> +	struct drm_mode_config *mode_config = &dev->mode_config;
> +	unsigned long irqflags;
> +	int i;
> +
> +	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
> +	for (i = 1; i < HPD_NUM_PINS; i++) {

Maybe include a small comment to avoid people thinking the 'i = 1' is
a typo.

> +		if (dev_priv->hpd_stats[i].hpd_mark == HPD_MARK_DISABLED) {

This is getting quite deep. This could help a bit:

if (dev_priv->hpd_stats[i].hpd_mark != HPD_MARK_DISABLED)
	continue;

> +			struct drm_connector *connector;
> +
> +			dev_priv->hpd_stats[i].hpd_mark = HPD_ENABLED;
> +			list_for_each_entry(connector, &mode_config->connector_list, head) {
> +				struct intel_connector *intel_connector = to_intel_connector(connector);
> +
> +				if (intel_connector->encoder->hpd_pin == i) {
> +					if (connector->polled != intel_connector->polled)
> +						DRM_DEBUG_DRIVER("Reenabling HPD on connector %s\n",
> +							 drm_get_connector_name(connector));
> +					connector->polled = intel_connector->polled;
> +					if (!connector->polled)
> +						connector->polled = DRM_CONNECTOR_POLL_HPD;
> +				}
> +			}
> +
> +			if (IS_HASWELL(dev) ||
> +			    IS_IVYBRIDGE(dev) ||
> +			    (HAS_PCH_SPLIT(dev)))

IS_HASWELL() and IS_IVYBRIDGE() are superfluous.

> +				ibx_hpd_irq_setup(dev);
> +			else
> +				i915_hpd_irq_setup(dev);
> +		}
> +	}
> +	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
> +}
> +
>  void intel_irq_init(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> @@ -2878,6 +2927,8 @@ void intel_irq_init(struct drm_device *dev)
>  	setup_timer(&dev_priv->gpu_error.hangcheck_timer,
>  		    i915_hangcheck_elapsed,
>  		    (unsigned long) dev);
> +	setup_timer(&dev_priv->hotplug_reenable_timer, i915_reenable_hotplug_timer_func,
> +		    (unsigned long) dev_priv);
>  
>  	pm_qos_add_request(&dev_priv->pm_qos, PM_QOS_CPU_DMA_LATENCY, PM_QOS_DEFAULT_VALUE);
>  
> -- 
> 1.7.7
> 
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-- 
Ville Syrjälä
Intel OTC