[Intel-gfx] [PATCH 1/3] drm/i915: don't block resume on fb console resume

[Jesse Barnes]

The console lock can be contended, so rather than prevent other drivers
after us from being held up, queue the console suspend into the global
work queue that can happen anytime.  I've measured this to take around
200ms on my T420.  Combined with the ring freq/turbo change, we should
save almost 1/2 a second on resume.

Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
---
 drivers/gpu/drm/i915/i915_dma.c |    3 +++
 drivers/gpu/drm/i915/i915_drv.c |   17 ++++++++++++++---
 drivers/gpu/drm/i915/i915_drv.h |    7 +++++++
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 491394f..f88bfa6 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1327,6 +1327,8 @@ static int i915_load_modeset_init(struct drm_device *dev)
 
 	intel_modeset_gem_init(dev);
 
+	INIT_WORK(&dev_priv->console_resume_work, intel_console_resume);
+
 	ret = drm_irq_install(dev);
 	if (ret)
 		goto cleanup_gem;
@@ -1721,6 +1723,7 @@ int i915_driver_unload(struct drm_device *dev)
 	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
 		intel_fbdev_fini(dev);
 		intel_modeset_cleanup(dev);
+		cancel_work_sync(&dev_priv->console_resume_work);
 
 		/*
 		 * free the memory space allocated for the child device
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index a7837e5..824e3c8 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -520,6 +520,18 @@ int i915_suspend(struct drm_device *dev, pm_message_t state)
 	return 0;
 }
 
+void intel_console_resume(struct work_struct *work)
+{
+	struct drm_i915_private *dev_priv =
+		container_of(work, struct drm_i915_private,
+			     console_resume_work);
+	struct drm_device *dev = dev_priv->dev;
+
+	console_lock();
+	intel_fbdev_set_suspend(dev, 0);
+	console_unlock();
+}
+
 static int i915_drm_thaw(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -555,9 +567,8 @@ static int i915_drm_thaw(struct drm_device *dev)
 
 	dev_priv->modeset_on_lid = 0;
 
-	console_lock();
-	intel_fbdev_set_suspend(dev, 0);
-	console_unlock();
+	schedule_work(&dev_priv->console_resume_work);
+
 	return error;
 }
 
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 9e446b6..e22b9e3 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -453,6 +453,12 @@ typedef struct drm_i915_private {
 	u32 hotplug_supported_mask;
 	struct work_struct hotplug_work;
 
+	/*
+	 * The console may be contended at resume, but we don't
+	 * want it to block on it.
+	 */
+	struct work_struct console_resume_work;
+
 	int num_pipe;
 	int num_pch_pll;
 
@@ -1257,6 +1263,7 @@ extern unsigned long i915_mch_val(struct drm_i915_private *dev_priv);
 extern unsigned long i915_gfx_val(struct drm_i915_private *dev_priv);
 extern void i915_update_gfx_val(struct drm_i915_private *dev_priv);
 
+extern void intel_console_resume(struct work_struct *work);
 
 /* i915_irq.c */
 void i915_hangcheck_elapsed(unsigned long data);
-- 
1.7.9.5