From a65e34c79c88895766ab1f8a5afa451eed26622b Mon Sep 17 00:00:00 2001 From: Keith Packard Date: Mon, 25 Jul 2011 10:04:56 -0700 Subject: drm/i915: Hold mode_config->mutex during hotplug processing Hotplug detection is a mode setting operation and must hold the struct_mutex or risk colliding with other mode setting operations. In particular, the display port hotplug function attempts to re-train the link if the monitor is supposed to be running when plugged back in. If that happens while mode setting is underway, the link will get scrambled, leaving it in an inconsistent state. This is a special case -- usually the driver mode setting entry points are covered by the upper level DRM code, but in this case the function is invoked as a work function not under the control of DRM. Signed-off-by: Keith Packard Cc: stable@kernel.org Reviewed-by: Jesse Barnes --- drivers/gpu/drm/i915/i915_irq.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/gpu/drm/i915/i915_irq.c') diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index 3b03f85ea62..9da2a2c9995 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -306,6 +306,7 @@ static void i915_hotplug_work_func(struct work_struct *work) struct drm_mode_config *mode_config = &dev->mode_config; struct intel_encoder *encoder; + mutex_lock(&mode_config->mutex); DRM_DEBUG_KMS("running encoder hotplug functions\n"); list_for_each_entry(encoder, &mode_config->encoder_list, base.head) @@ -314,6 +315,8 @@ static void i915_hotplug_work_func(struct work_struct *work) /* Just fire off a uevent and let userspace tell us what to do */ drm_helper_hpd_irq_event(dev); + + mutex_unlock(&mode_config->mutex); } static void i915_handle_rps_change(struct drm_device *dev) -- cgit v1.2.3-70-g09d2 From 40ee3381dd1010432acc13e907329029096c5bfc Mon Sep 17 00:00:00 2001 From: Keith Packard Date: Thu, 28 Jul 2011 15:31:19 -0700 Subject: drm/i915: Fixup for 'Hold mode_config->mutex during hotplug' drm_helper_hpd_irq_event queues another work proc to go and deliver the user-space event, and that function also wants to hold the config mutex, so we shouldn't hold the mutex across the drm_helper_hpd_irq_event call. Signed-off-by: Keith Packard --- drivers/gpu/drm/i915/i915_irq.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm/i915/i915_irq.c') diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index 9da2a2c9995..9b1d669f7d4 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -313,10 +313,10 @@ static void i915_hotplug_work_func(struct work_struct *work) if (encoder->hot_plug) encoder->hot_plug(encoder); + mutex_unlock(&mode_config->mutex); + /* Just fire off a uevent and let userspace tell us what to do */ drm_helper_hpd_irq_event(dev); - - mutex_unlock(&mode_config->mutex); } static void i915_handle_rps_change(struct drm_device *dev) -- cgit v1.2.3-70-g09d2