[PATCH 05/19] drm/i915: make PC8 be part of runtime PM suspend/resume

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From: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>

Currently, when our driver becomes idle for i915_pc8_timeout (default:
5s) we enable PC8, so we save some power, but not everything we can.
Then, while PC8 is enabled, if we stay idle for more
autosuspend_delay_ms (default: 10s) we'll enter runtime PM and put the
graphics device in D3 state, saving even more power. The two features
are separate things with increasing levels of power savings, but if we
disable PC8 we'll never get into D3.

While from the modularity point of view it would be nice to keep these
features as separate, we have reasons to merge them:
 - We are not aware of anybody wanting a "PC8 without D3" environment.
 - If we keep both features as separate, we'll have to to test both
   PC8 and PC8+D3 code paths. We're already having a major pain to
   make QA do automated testing of just one thing, testing both paths
   will cost even more.
 - Only Haswell+ supports PC8, so if we want to add runtime PM support
   to, for example, IVB, we'll have to copy some code from the PC8
   feature to runtime PM, so merging both features as a single tihng
   will make it easier for enabling runtime PM on other platforms.

This patch only does the very basic steps required to have PC8 and
runtime PM merged on a single feature: the next patches will take care
of cleaning up everything.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
---
 drivers/gpu/drm/i915/i915_dma.c      |  2 --
 drivers/gpu/drm/i915/i915_drv.c      | 14 +++++++++---
 drivers/gpu/drm/i915/i915_drv.h      |  7 +++---
 drivers/gpu/drm/i915/intel_display.c | 43 ++++++++----------------------------
 drivers/gpu/drm/i915/intel_drv.h     |  3 ++-
 drivers/gpu/drm/i915/intel_pm.c      |  1 -
 6 files changed, 26 insertions(+), 44 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index ee9502b..ae6a622 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1760,8 +1760,6 @@ int i915_driver_unload(struct drm_device *dev)
 	cancel_work_sync(&dev_priv->gpu_error.work);
 	i915_destroy_error_state(dev);
 
-	cancel_delayed_work_sync(&dev_priv->pc8.enable_work);
-
 	if (dev->pdev->msi_enabled)
 		pci_disable_msi(dev->pdev);
 
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 61fb9fc..3b86541 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -144,11 +144,11 @@ MODULE_PARM_DESC(fastboot, "Try to skip unnecessary mode sets at boot time "
 
 int i915_enable_pc8 __read_mostly = 1;
 module_param_named(enable_pc8, i915_enable_pc8, int, 0600);
-MODULE_PARM_DESC(enable_pc8, "Enable support for low power package C states (PC8+) (default: true)");
+MODULE_PARM_DESC(enable_pc8, "Ignored. Deprecated by runtime PM support.");
 
-int i915_pc8_timeout __read_mostly = 5000;
+int i915_pc8_timeout __read_mostly = 0;
 module_param_named(pc8_timeout, i915_pc8_timeout, int, 0600);
-MODULE_PARM_DESC(pc8_timeout, "Number of msecs of idleness required to enter PC8+ (default: 5000)");
+MODULE_PARM_DESC(pc8_timeout, "Ignored. Deprecated by runtime PM autosuspend delay.");
 
 bool i915_prefault_disable __read_mostly;
 module_param_named(prefault_disable, i915_prefault_disable, bool, 0600);
@@ -921,12 +921,16 @@ static int i915_runtime_suspend(struct device *device)
 
 	DRM_DEBUG_KMS("Suspending device\n");
 
+	if (HAS_PC8(dev))
+		__hsw_do_enable_pc8(dev_priv);
+
 	i915_gem_release_all_mmaps(dev_priv);
 
 	del_timer_sync(&dev_priv->gpu_error.hangcheck_timer);
 	dev_priv->pm.suspended = true;
 	intel_opregion_notify_adapter(dev, PCI_D3cold);
 
+	DRM_DEBUG_KMS("Device suspended\n");
 	return 0;
 }
 
@@ -943,6 +947,10 @@ static int i915_runtime_resume(struct device *device)
 	intel_opregion_notify_adapter(dev, PCI_D0);
 	dev_priv->pm.suspended = false;
 
+	if (HAS_PC8(dev))
+		__hsw_do_disable_pc8(dev_priv);
+
+	DRM_DEBUG_KMS("Device resumed\n");
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 7f8ec08..b05e07b 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1256,6 +1256,10 @@ struct ilk_wm_values {
 /*
  * This struct tracks the state needed for the Package C8+ feature.
  *
+ * TODO: we're merging the Package C8+ feature with the runtime PM support. To
+ * avoid having to update the documentation at each patch of the series, we'll
+ * do a final update at the end.
+ *
  * Package states C8 and deeper are really deep PC states that can only be
  * reached when all the devices on the system allow it, so even if the graphics
  * device allows PC8+, it doesn't mean the system will actually get to these
@@ -1311,7 +1315,6 @@ struct i915_package_c8 {
 	bool enabled;
 	int disable_count;
 	struct mutex lock;
-	struct delayed_work enable_work;
 
 	struct {
 		uint32_t deimr;
@@ -1915,8 +1918,6 @@ extern unsigned int i915_preliminary_hw_support __read_mostly;
 extern int i915_disable_power_well __read_mostly;
 extern int i915_enable_ips __read_mostly;
 extern bool i915_fastboot __read_mostly;
-extern int i915_enable_pc8 __read_mostly;
-extern int i915_pc8_timeout __read_mostly;
 extern bool i915_prefault_disable __read_mostly;
 
 extern int i915_suspend(struct drm_device *dev, pm_message_t state);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index db6523e..5055a71 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6601,7 +6601,7 @@ static void hsw_restore_lcpll(struct drm_i915_private *dev_priv)
 
 	/* Make sure we're not on PC8 state before disabling PC8, otherwise
 	 * we'll hang the machine! */
-	gen6_gt_force_wake_get(dev_priv, FORCEWAKE_ALL);
+	gen6_gt_force_wake_get_no_rpm(dev_priv, FORCEWAKE_ALL);
 
 	if (val & LCPLL_POWER_DOWN_ALLOW) {
 		val &= ~LCPLL_POWER_DOWN_ALLOW;
@@ -6635,14 +6635,16 @@ static void hsw_restore_lcpll(struct drm_i915_private *dev_priv)
 			DRM_ERROR("Switching back to LCPLL failed\n");
 	}
 
-	gen6_gt_force_wake_put(dev_priv, FORCEWAKE_ALL);
+	gen6_gt_force_wake_put_no_rpm(dev_priv, FORCEWAKE_ALL);
 }
 
-static void __hsw_do_enable_pc8(struct drm_i915_private *dev_priv)
+void __hsw_do_enable_pc8(struct drm_i915_private *dev_priv)
 {
 	struct drm_device *dev = dev_priv->dev;
 	uint32_t val;
 
+	WARN_ON(!HAS_PC8(dev));
+
 	DRM_DEBUG_KMS("Enabling package C8+\n");
 
 	dev_priv->pc8.enabled = true;
@@ -6658,22 +6660,6 @@ static void __hsw_do_enable_pc8(struct drm_i915_private *dev_priv)
 	hsw_disable_lcpll(dev_priv, true, true);
 }
 
-void hsw_enable_pc8_work(struct work_struct *__work)
-{
-	struct drm_i915_private *dev_priv =
-		container_of(to_delayed_work(__work), struct drm_i915_private,
-			     pc8.enable_work);
-	struct drm_device *dev = dev_priv->dev;
-
-	WARN_ON(!HAS_PC8(dev));
-
-	if (dev_priv->pc8.enabled)
-		return;
-
-	__hsw_do_enable_pc8(dev_priv);
-	intel_runtime_pm_put(dev_priv);
-}
-
 static void __hsw_enable_package_c8(struct drm_i915_private *dev_priv)
 {
 	WARN_ON(!mutex_is_locked(&dev_priv->pc8.lock));
@@ -6684,15 +6670,16 @@ static void __hsw_enable_package_c8(struct drm_i915_private *dev_priv)
 	if (dev_priv->pc8.disable_count != 0)
 		return;
 
-	schedule_delayed_work(&dev_priv->pc8.enable_work,
-			      msecs_to_jiffies(i915_pc8_timeout));
+	intel_runtime_pm_put(dev_priv);
 }
 
-static void __hsw_do_disable_package_c8(struct drm_i915_private *dev_priv)
+void __hsw_do_disable_pc8(struct drm_i915_private *dev_priv)
 {
 	struct drm_device *dev = dev_priv->dev;
 	uint32_t val;
 
+	WARN_ON(!HAS_PC8(dev));
+
 	DRM_DEBUG_KMS("Disabling package C8+\n");
 
 	hsw_restore_lcpll(dev_priv);
@@ -6715,8 +6702,6 @@ static void __hsw_do_disable_package_c8(struct drm_i915_private *dev_priv)
 
 static void __hsw_disable_package_c8(struct drm_i915_private *dev_priv)
 {
-	struct drm_device *dev = dev_priv->dev;
-
 	WARN_ON(!mutex_is_locked(&dev_priv->pc8.lock));
 	WARN(dev_priv->pc8.disable_count < 0,
 	     "pc8.disable_count: %d\n", dev_priv->pc8.disable_count);
@@ -6725,14 +6710,7 @@ static void __hsw_disable_package_c8(struct drm_i915_private *dev_priv)
 	if (dev_priv->pc8.disable_count != 1)
 		return;
 
-	WARN_ON(!HAS_PC8(dev));
-
-	cancel_delayed_work_sync(&dev_priv->pc8.enable_work);
-	if (!dev_priv->pc8.enabled)
-		return;
-
 	intel_runtime_pm_get(dev_priv);
-	__hsw_do_disable_package_c8(dev_priv);
 }
 
 void hsw_enable_package_c8(struct drm_i915_private *dev_priv)
@@ -6790,9 +6768,6 @@ static void hsw_update_package_c8(struct drm_device *dev)
 	if (!HAS_PC8(dev_priv->dev))
 		return;
 
-	if (!i915_enable_pc8)
-		return;
-
 	mutex_lock(&dev_priv->pc8.lock);
 
 	allow = hsw_can_enable_package_c8(dev_priv);
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 46aea6c..6985126 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -694,7 +694,8 @@ unsigned long intel_gen4_compute_page_offset(int *x, int *y,
 					     unsigned int bpp,
 					     unsigned int pitch);
 void intel_display_handle_reset(struct drm_device *dev);
-void hsw_enable_pc8_work(struct work_struct *__work);
+void __hsw_do_enable_pc8(struct drm_i915_private *dev_priv);
+void __hsw_do_disable_pc8(struct drm_i915_private *dev_priv);
 void hsw_enable_package_c8(struct drm_i915_private *dev_priv);
 void hsw_disable_package_c8(struct drm_i915_private *dev_priv);
 void intel_dp_get_m_n(struct intel_crtc *crtc,
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 469170c..c644a6f 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5785,7 +5785,6 @@ void intel_pm_setup(struct drm_device *dev)
 	dev_priv->pc8.irqs_disabled = false;
 	dev_priv->pc8.enabled = false;
 	dev_priv->pc8.disable_count = 2; /* requirements_met + gpu_idle */
-	INIT_DELAYED_WORK(&dev_priv->pc8.enable_work, hsw_enable_pc8_work);
 	INIT_DELAYED_WORK(&dev_priv->rps.delayed_resume_work,
 			  intel_gen6_powersave_work);
 }
-- 
1.8.3.1

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