Re: [PATCH] drm/i915: Synchronize connectors states when switching from poll to irq

From: Paul Kocialkowski
Date: Tue Jul 18 2017 - 08:11:54 EST


On Mon, 2017-06-26 at 15:32 +0300, Paul Kocialkowski wrote:
> After detecting an IRQ storm, hotplug detection will switch from
> irq-based detection to poll-based detection. After a short delay or
> when resetting storm detection from debugfs, detection will switch
> back to being irq-based.
>
> However, it may occur that polling does not have enough time to detect
> the current connector state when that second switch takes place. Thus,
> this sets the appropriate hotplug event bits for the concerned
> connectors and schedules the hotplug work, that will ensure the
> connectors states are in sync when switching back to irq.
>
> Without this, no irq will be triggered and the hpd change will be
> lost.

Does anyone have feedback to provide on this?
It looks like it should be a no-brainer.

Cheers,

Paul

> Signed-off-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_hotplug.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_hotplug.c
> b/drivers/gpu/drm/i915/intel_hotplug.c
> index f1200272a699..29f55480b0bb 100644
> --- a/drivers/gpu/drm/i915/intel_hotplug.c
> +++ b/drivers/gpu/drm/i915/intel_hotplug.c
> @@ -218,9 +218,13 @@ static void
> intel_hpd_irq_storm_reenable_work(struct work_struct *work)
> struct intel_connector *intel_connector =
> to_intel_connector(connector);
>
> if (intel_connector->encoder->hpd_pin == i) {
> - if (connector->polled !=
> intel_connector->polled)
> + if (connector->polled !=
> intel_connector->polled) {
> DRM_DEBUG_DRIVER("Reenabling
> HPD on connector %s\n",
> connector-
> >name);
> +
> + dev_priv->hotplug.event_bits
> |= (1 << i);
> + }
> +
> connector->polled = intel_connector-
> >polled;
> if (!connector->polled)
> connector->polled =
> DRM_CONNECTOR_POLL_HPD;
> @@ -232,6 +236,8 @@ static void
> intel_hpd_irq_storm_reenable_work(struct work_struct *work)
> dev_priv->display.hpd_irq_setup(dev_priv);
> spin_unlock_irq(&dev_priv->irq_lock);
>
> + schedule_work(&dev_priv->hotplug.hotplug_work);
> +
> intel_runtime_pm_put(dev_priv);
> }
>
--
Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxxxxxx>
Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo, Finland