[PATCH 2/3] drm/i915: put ring frequency and turbo setup into a work queue v2

[Jesse Barnes <jbarnes@virtuousgeek.org>]

Communicating via the mailbox registers with the PCU can take quite
awhile.  And updating the ring frequency or enabling turbo is not
something that needs to happen synchronously, so take it out of our init
and resume paths to speed things up (~200ms on my T420).

v2: add comment about why we use a work queue (Daniel)
    make sure work queue is idle on suspend (Daniel)
    use a delayed work queue since there's no hurry (Daniel)

References: https://bugs.freedesktop.org/show_bug.cgi?id=54089

Signed-of-by: Jesse Barnes <jbarnes@virtuougseek.org>
---
 drivers/gpu/drm/i915/i915_dma.c |    1 +
 drivers/gpu/drm/i915/i915_drv.c |    2 ++
 drivers/gpu/drm/i915/i915_drv.h |    3 +++
 drivers/gpu/drm/i915/intel_pm.c |   32 ++++++++++++++++++++++++++++++--
 4 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 14526dc..b5977b4 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1725,6 +1725,7 @@ int i915_driver_unload(struct drm_device *dev)
 	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
 		intel_fbdev_fini(dev);
 		intel_modeset_cleanup(dev);
+		intel_gt_cleanup(dev);
 		cancel_work_sync(&dev_priv->console_resume_work);
 
 		/*
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 6d1fb51..4d858a9 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -470,6 +470,8 @@ static int i915_drm_freeze(struct drm_device *dev)
 			return error;
 		}
 
+		intel_gt_cleanup(dev);
+
 		intel_modeset_disable(dev);
 
 		drm_irq_uninstall(dev);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a5b0456..1e84a59 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -871,6 +871,8 @@ typedef struct drm_i915_private {
 		int r_t;
 	} ips;
 
+	struct delayed_work gen6_power_work;
+
 	enum no_fbc_reason no_fbc_reason;
 
 	struct drm_mm_node *compressed_fb;
@@ -1268,6 +1270,7 @@ void i915_handle_error(struct drm_device *dev, bool wedged);
 extern void intel_irq_init(struct drm_device *dev);
 extern void intel_gt_init(struct drm_device *dev);
 extern void intel_gt_reset(struct drm_device *dev);
+extern void intel_gt_cleanup(struct drm_device *dev);
 
 void i915_error_state_free(struct kref *error_ref);
 
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 59068be..025abbf 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3312,15 +3312,34 @@ void intel_disable_gt_powersave(struct drm_device *dev)
 	}
 }
 
+static void intel_gen6_powersave_work(struct work_struct *work)
+{
+	struct drm_i915_private *dev_priv =
+		container_of(work, struct drm_i915_private,
+			     gen6_power_work.work);
+	struct drm_device *dev = dev_priv->dev;
+
+	mutex_lock(&dev->struct_mutex);
+	gen6_enable_rps(dev);
+	gen6_update_ring_freq(dev);
+	mutex_unlock(&dev->struct_mutex);
+}
+
 void intel_enable_gt_powersave(struct drm_device *dev)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
 	if (IS_IRONLAKE_M(dev)) {
 		ironlake_enable_drps(dev);
 		ironlake_enable_rc6(dev);
 		intel_init_emon(dev);
 	} else if ((IS_GEN6(dev) || IS_GEN7(dev)) && !IS_VALLEYVIEW(dev)) {
-		gen6_enable_rps(dev);
-		gen6_update_ring_freq(dev);
+		/*
+		 * PCU communication is slow and this doesn't need to be
+		 * done at any specific time, so do this out of our fast path
+		 * to make resume and init faster.
+		 */
+		schedule_delayed_work(&dev_priv->gen6_power_work, HZ);
 	}
 }
 
@@ -4175,6 +4194,15 @@ void intel_gt_init(struct drm_device *dev)
 		dev_priv->gt.force_wake_get = __gen6_gt_force_wake_get;
 		dev_priv->gt.force_wake_put = __gen6_gt_force_wake_put;
 	}
+	INIT_DELAYED_WORK(&dev_priv->gen6_power_work,
+			  intel_gen6_powersave_work);
+}
+
+void intel_gt_cleanup(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	cancel_delayed_work_sync(&dev_priv->gen6_power_work);
 }
 
 int sandybridge_pcode_read(struct drm_i915_private *dev_priv, u8 mbox, u32 *val)
-- 
1.7.9.5