One of the things preventing us from using polling is the fact that calling valleyview_crt_detect_hotplug() when there's a VGA cable connected results in sending another hotplug. With polling enabled when HPD is disabled, this results in a scenario like this: - We enable power wells and reset the ADPA - output_poll_exec does force probe on VGA, triggering a hpd - HPD handler waits for poll to unlock dev->mode_config.mutex - output_poll_exec shuts off the ADPA, unlocks dev->mode_config.mutex - HPD handler runs, resets ADPA and brings us back to the start This results in an endless irq storm getting sent from the ADPA whenever a VGA connector gets detected in the middle of polling. Somewhat based off of the "drm/i915: Disable CRT HPD around force trigger" patch Ville Syrjälä sent a while back Cc: stable@xxxxxxxxxxxxxxx Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Signed-off-by: Lyude <cpaul@xxxxxxxxxx> --- drivers/gpu/drm/i915/i915_drv.h | 2 ++ drivers/gpu/drm/i915/intel_crt.c | 18 ++++++++++++++++++ drivers/gpu/drm/i915/intel_hotplug.c | 27 +++++++++++++++++++++++++++ 3 files changed, 47 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index a988a95..239a3ec 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -2933,6 +2933,8 @@ void intel_hpd_init(struct drm_i915_private *dev_priv); void intel_hpd_init_work(struct drm_i915_private *dev_priv); void intel_hpd_cancel_work(struct drm_i915_private *dev_priv); bool intel_hpd_pin_to_port(enum hpd_pin pin, enum port *port); +bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin); +void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin); /* i915_irq.c */ void i915_queue_hangcheck(struct drm_i915_private *dev_priv); diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c index 220be7a..a626793 100644 --- a/drivers/gpu/drm/i915/intel_crt.c +++ b/drivers/gpu/drm/i915/intel_crt.c @@ -327,10 +327,25 @@ static bool valleyview_crt_detect_hotplug(struct drm_connector *connector) struct drm_device *dev = connector->dev; struct intel_crt *crt = intel_attached_crt(connector); struct drm_i915_private *dev_priv = dev->dev_private; + bool reenable_hpd; u32 adpa; bool ret; u32 save_adpa; + /* + * Doing a force trigger causes a hpd interrupt to get sent, which can + * get us stuck in a loop if we're polling: + * - We enable power wells and reset the ADPA + * - output_poll_exec does force probe on VGA, triggering a hpd + * - HPD handler waits for poll to unlock dev->mode_config.mutex + * - output_poll_exec shuts off the ADPA, unlocks + * dev->mode_config.mutex + * - HPD handler runs, resets ADPA and brings us back to the start + * + * Just disable HPD interrupts here to prevent this + */ + reenable_hpd = intel_hpd_disable(dev_priv, crt->base.hpd_pin); + save_adpa = adpa = I915_READ(crt->adpa_reg); DRM_DEBUG_KMS("trigger hotplug detect cycle: adpa=0x%x\n", adpa); @@ -353,6 +368,9 @@ static bool valleyview_crt_detect_hotplug(struct drm_connector *connector) DRM_DEBUG_KMS("valleyview hotplug adpa=0x%x, result %d\n", adpa, ret); + if (reenable_hpd) + intel_hpd_enable(dev_priv, crt->base.hpd_pin); + return ret; } diff --git a/drivers/gpu/drm/i915/intel_hotplug.c b/drivers/gpu/drm/i915/intel_hotplug.c index 38eeca7..ec3285f 100644 --- a/drivers/gpu/drm/i915/intel_hotplug.c +++ b/drivers/gpu/drm/i915/intel_hotplug.c @@ -510,3 +510,30 @@ void intel_hpd_cancel_work(struct drm_i915_private *dev_priv) cancel_work_sync(&dev_priv->hotplug.hotplug_work); cancel_delayed_work_sync(&dev_priv->hotplug.reenable_work); } + +bool intel_hpd_disable(struct drm_i915_private *dev_priv, enum hpd_pin pin) +{ + bool ret = false; + + if (pin == HPD_NONE) + return false; + + spin_lock_irq(&dev_priv->irq_lock); + if (dev_priv->hotplug.stats[pin].state == HPD_ENABLED) { + dev_priv->hotplug.stats[pin].state = HPD_DISABLED; + ret = true; + } + spin_unlock_irq(&dev_priv->irq_lock); + + return ret; +} + +void intel_hpd_enable(struct drm_i915_private *dev_priv, enum hpd_pin pin) +{ + if (pin == HPD_NONE) + return; + + spin_lock_irq(&dev_priv->irq_lock); + dev_priv->hotplug.stats[pin].state = HPD_ENABLED; + spin_unlock_irq(&dev_priv->irq_lock); +} -- 2.5.5 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html