[CI,v2,4/5] drm/i915: Introduce a non-blocking power domain for vblank interrupts

Commit Message

Dhinakaran Pandiyan Dec. 18, 2017, 10:24 a.m. UTC

When DC states are enabled and PSR is active, the hardware enters DC5/DC6
states resulting in frame counter resets. The frame counter resets mess
up the vblank counting logic. So in order to disable DC states when
vblank interrupts are required and to disallow DC states when vblanks
interrupts are already enabled, introduce a new power domain. Since this
power domain reference needs to be acquired and released in atomic context,
the corresponding _get() and _put() methods skip the power_domain mutex.

Signed-off-by: Dhinakaran Pandiyan <[e-mail]>
---
 drivers/gpu/drm/i915/i915_drv.h         |   8 ++
 drivers/gpu/drm/i915/intel_drv.h        |   3 +
 drivers/gpu/drm/i915/intel_runtime_pm.c | 196 +++++++++++++++++++++++++++++---
 3 files changed, 193 insertions(+), 14 deletions(-)

Patch

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a10f31c9e4a9..5494582fdfea 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -397,6 +397,7 @@  enum intel_display_power_domain {
 	POWER_DOMAIN_AUX_C,
 	POWER_DOMAIN_AUX_D,
 	POWER_DOMAIN_GMBUS,
+	POWER_DOMAIN_VBLANK,
 	POWER_DOMAIN_MODESET,
 	POWER_DOMAIN_GT_IRQ,
 	POWER_DOMAIN_INIT,
@@ -1476,7 +1477,14 @@  struct i915_power_well {
 			bool has_vga:1;
 			bool has_fuses:1;
 		} hsw;
+		struct {
+			bool was_disabled;
+		} dc_off;
 	};
+
+	spinlock_t lock;
+	bool supports_atomic_ctx;
+
 	const struct i915_power_well_ops *ops;
 };
 
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 30f791f89d64..164e62cb047b 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1797,6 +1797,9 @@  bool intel_display_power_get_if_enabled(struct drm_i915_private *dev_priv,
 					enum intel_display_power_domain domain);
 void intel_display_power_put(struct drm_i915_private *dev_priv,
 			     enum intel_display_power_domain domain);
+void intel_display_power_vblank_get(struct drm_i915_private *dev_priv,
+				    bool *needs_restore);
+void intel_display_power_vblank_put(struct drm_i915_private *dev_priv);
 
 static inline void
 assert_rpm_device_not_suspended(struct drm_i915_private *dev_priv)
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 992caec1fbc4..9cbb332cb418 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -56,6 +56,16 @@  static struct i915_power_well *
 lookup_power_well(struct drm_i915_private *dev_priv,
 		  enum i915_power_well_id power_well_id);
 
+/* optimize for the case when this function is called from atomic context,
+ * although this is unlikely */
+#define power_well_lock(power_well, flags)			\
+	if (likely(power_well->supports_atomic_ctx))		\
+		spin_lock_irqsave(&power_well->lock, flags)
+
+#define power_well_unlock(power_well, flags)			\
+	if (likely(power_well->supports_atomic_ctx))		\
+		spin_unlock_irqrestore(&power_well->lock, flags)
+
 const char *
 intel_display_power_domain_str(enum intel_display_power_domain domain)
 {
@@ -126,6 +136,8 @@  intel_display_power_domain_str(enum intel_display_power_domain domain)
 		return "AUX_D";
 	case POWER_DOMAIN_GMBUS:
 		return "GMBUS";
+	case POWER_DOMAIN_VBLANK:
+		return "VBLANK";
 	case POWER_DOMAIN_INIT:
 		return "INIT";
 	case POWER_DOMAIN_MODESET:
@@ -141,6 +153,9 @@  intel_display_power_domain_str(enum intel_display_power_domain domain)
 static void intel_power_well_enable(struct drm_i915_private *dev_priv,
 				    struct i915_power_well *power_well)
 {
+	if (power_well->supports_atomic_ctx)
+		assert_spin_locked(&power_well->lock);
+
 	DRM_DEBUG_KMS("enabling %s\n", power_well->name);
 	power_well->ops->enable(dev_priv, power_well);
 	power_well->hw_enabled = true;
@@ -149,19 +164,34 @@  static void intel_power_well_enable(struct drm_i915_private *dev_priv,
 static void intel_power_well_disable(struct drm_i915_private *dev_priv,
 				     struct i915_power_well *power_well)
 {
+	if (power_well->supports_atomic_ctx)
+		assert_spin_locked(&power_well->lock);
+
 	DRM_DEBUG_KMS("disabling %s\n", power_well->name);
 	power_well->hw_enabled = false;
 	power_well->ops->disable(dev_priv, power_well);
 }
 
-static void intel_power_well_get(struct drm_i915_private *dev_priv,
+
+static void __intel_power_well_get(struct drm_i915_private *dev_priv,
 				 struct i915_power_well *power_well)
 {
 	if (!power_well->count++)
 		intel_power_well_enable(dev_priv, power_well);
 }
 
-static void intel_power_well_put(struct drm_i915_private *dev_priv,
+
+static void intel_power_well_get(struct drm_i915_private *dev_priv,
+				 struct i915_power_well *power_well)
+{
+	unsigned long flags = 0;
+
+	power_well_lock(power_well, flags);
+	__intel_power_well_get(dev_priv, power_well);
+	power_well_unlock(power_well, flags);
+}
+
+static void __intel_power_well_put(struct drm_i915_private *dev_priv,
 				 struct i915_power_well *power_well)
 {
 	WARN(!power_well->count, "Use count on power well %s is already zero",
@@ -171,6 +201,16 @@  static void intel_power_well_put(struct drm_i915_private *dev_priv,
 		intel_power_well_disable(dev_priv, power_well);
 }
 
+static void intel_power_well_put(struct drm_i915_private *dev_priv,
+				 struct i915_power_well *power_well)
+{
+	unsigned long flags = 0;
+
+	power_well_lock(power_well, flags);
+	__intel_power_well_put(dev_priv, power_well);
+	power_well_unlock(power_well, flags);
+}
+
 /**
  * __intel_display_power_is_enabled - unlocked check for a power domain
  * @dev_priv: i915 device instance
@@ -726,6 +766,7 @@  static void gen9_dc_off_power_well_disable(struct drm_i915_private *dev_priv,
 		skl_enable_dc6(dev_priv);
 	else if (dev_priv->csr.allowed_dc_mask & DC_STATE_EN_UPTO_DC5)
 		gen9_enable_dc5(dev_priv);
+	power_well->dc_off.was_disabled = true;
 }
 
 static void i9xx_power_well_sync_hw_noop(struct drm_i915_private *dev_priv,
@@ -1443,6 +1484,63 @@  static void chv_pipe_power_well_disable(struct drm_i915_private *dev_priv,
 	chv_set_pipe_power_well(dev_priv, power_well, false);
 }
 
+#define CAN_PSR(dev_priv) (HAS_PSR(dev_priv) && dev_priv->psr.sink_support)
+void intel_display_power_vblank_get(struct drm_i915_private *dev_priv,
+				    bool *needs_restore)
+{
+	struct i915_power_domains *power_domains  = &dev_priv->power_domains;
+	struct i915_power_well *power_well;
+
+	*needs_restore = false;
+
+	if (!HAS_CSR(dev_priv))
+		return;
+
+	if (!CAN_PSR(dev_priv))
+		return;
+
+	intel_runtime_pm_get_noresume(dev_priv);
+
+	for_each_power_domain_well(dev_priv, power_well, BIT_ULL(POWER_DOMAIN_VBLANK)) {
+		unsigned long flags = 0;
+
+		power_well_lock(power_well, flags);
+		__intel_power_well_get(dev_priv, power_well);
+		*needs_restore = power_well->dc_off.was_disabled;
+		power_well->dc_off.was_disabled = false;
+		power_well_unlock(power_well, flags);
+	}
+
+	atomic_inc(&power_domains->domain_use_count[POWER_DOMAIN_VBLANK]);
+}
+
+void intel_display_power_vblank_put(struct drm_i915_private *dev_priv)
+{
+	struct i915_power_domains *power_domains = &dev_priv->power_domains;
+	struct i915_power_well *power_well;
+
+	if (!HAS_CSR(dev_priv))
+		return;
+
+	if (!CAN_PSR(dev_priv))
+		return;
+
+	WARN(atomic_dec_return(&power_domains->domain_use_count[POWER_DOMAIN_VBLANK]) < 0,
+	     "Use count on domain %s was already zero\n",
+	     intel_display_power_domain_str(POWER_DOMAIN_VBLANK));
+
+	for_each_power_domain_well_rev(dev_priv, power_well, BIT_ULL(POWER_DOMAIN_VBLANK)) {
+		unsigned long flags = 0;
+
+		power_well_lock(power_well, flags);
+		__intel_power_well_put(dev_priv, power_well);
+		power_well_unlock(power_well, flags);
+	}
+
+	intel_runtime_pm_put(dev_priv);
+}
+#undef CAN_PSR
+
 static void
 __intel_display_power_get_domain(struct drm_i915_private *dev_priv,
 				 enum intel_display_power_domain domain)
@@ -1482,6 +1580,38 @@  void intel_display_power_get(struct drm_i915_private *dev_priv,
 	mutex_unlock(&power_domains->lock);
 }
 
+static bool dc_off_get_if_enabled(struct drm_i915_private *dev_priv,
+				  enum intel_display_power_domain domain)
+{
+	struct i915_power_well *power_well;
+	bool is_enabled;
+	unsigned long flags = 0;
+
+	power_well = lookup_power_well(dev_priv, SKL_DISP_PW_DC_OFF);
+	if (!power_well || !(power_well->domains & domain))
+		return true;
+
+	power_well_lock(power_well, flags);
+	is_enabled = power_well->hw_enabled;
+	if (is_enabled)
+		__intel_power_well_get(dev_priv, power_well);
+	power_well_unlock(power_well, flags);
+
+	return is_enabled;
+}
+
+static void dc_off_put(struct drm_i915_private *dev_priv,
+		       enum intel_display_power_domain domain)
+{
+	struct i915_power_well *power_well;
+
+	power_well = lookup_power_well(dev_priv, SKL_DISP_PW_DC_OFF);
+	if (!power_well || !(power_well->domains & domain))
+		return;
+
+	intel_power_well_put(dev_priv, power_well);
+}
+
 /**
  * intel_display_power_get_if_enabled - grab a reference for an enabled display power domain
  * @dev_priv: i915 device instance
@@ -1498,20 +1628,25 @@  bool intel_display_power_get_if_enabled(struct drm_i915_private *dev_priv,
 					enum intel_display_power_domain domain)
 {
 	struct i915_power_domains *power_domains = &dev_priv->power_domains;
-	bool is_enabled;
+	bool is_enabled = false;
+
 
 	if (!intel_runtime_pm_get_if_in_use(dev_priv))
 		return false;
 
 	mutex_lock(&power_domains->lock);
 
+	if (!dc_off_get_if_enabled(dev_priv, domain))
+		goto out;
+
 	if (__intel_display_power_is_enabled(dev_priv, domain)) {
 		__intel_display_power_get_domain(dev_priv, domain);
 		is_enabled = true;
-	} else {
-		is_enabled = false;
 	}
 
+	dc_off_put(dev_priv, domain);
+
+out:
 	mutex_unlock(&power_domains->lock);
 
 	if (!is_enabled)
@@ -1709,6 +1844,7 @@  void intel_display_power_put(struct drm_i915_private *dev_priv,
 	BIT_ULL(POWER_DOMAIN_GT_IRQ) |			\
 	BIT_ULL(POWER_DOMAIN_MODESET) |			\
 	BIT_ULL(POWER_DOMAIN_AUX_A) |			\
+	BIT_ULL(POWER_DOMAIN_VBLANK) |			\
 	BIT_ULL(POWER_DOMAIN_INIT))
 
 #define BXT_DISPLAY_POWERWELL_2_POWER_DOMAINS (		\
@@ -1732,6 +1868,7 @@  void intel_display_power_put(struct drm_i915_private *dev_priv,
 	BIT_ULL(POWER_DOMAIN_GT_IRQ) |			\
 	BIT_ULL(POWER_DOMAIN_MODESET) |			\
 	BIT_ULL(POWER_DOMAIN_AUX_A) |			\
+	BIT_ULL(POWER_DOMAIN_VBLANK) |			\
 	BIT_ULL(POWER_DOMAIN_INIT))
 #define BXT_DPIO_CMN_A_POWER_DOMAINS (			\
 	BIT_ULL(POWER_DOMAIN_PORT_DDI_A_LANES) |		\
@@ -1791,6 +1928,7 @@  void intel_display_power_put(struct drm_i915_private *dev_priv,
 	BIT_ULL(POWER_DOMAIN_GT_IRQ) |			\
 	BIT_ULL(POWER_DOMAIN_MODESET) |			\
 	BIT_ULL(POWER_DOMAIN_AUX_A) |			\
+	BIT_ULL(POWER_DOMAIN_VBLANK) |			\
 	BIT_ULL(POWER_DOMAIN_INIT))
 
 #define CNL_DISPLAY_POWERWELL_2_POWER_DOMAINS (		\
@@ -1838,6 +1976,7 @@  void intel_display_power_put(struct drm_i915_private *dev_priv,
 	CNL_DISPLAY_POWERWELL_2_POWER_DOMAINS |		\
 	BIT_ULL(POWER_DOMAIN_MODESET) |			\
 	BIT_ULL(POWER_DOMAIN_AUX_A) |			\
+	BIT_ULL(POWER_DOMAIN_VBLANK) |			\
 	BIT_ULL(POWER_DOMAIN_INIT))
 
 static const struct i915_power_well_ops i9xx_always_on_power_well_ops = {
@@ -2071,9 +2210,12 @@  bool intel_display_power_well_is_enabled(struct drm_i915_private *dev_priv,
 {
 	struct i915_power_well *power_well;
 	bool ret;
+	unsigned long flags = 0;
 
 	power_well = lookup_power_well(dev_priv, power_well_id);
+	power_well_lock(power_well, flags);
 	ret = power_well->ops->is_enabled(dev_priv, power_well);
+	power_well_unlock(power_well, flags);
 
 	return ret;
 }
@@ -2108,6 +2250,7 @@  static struct i915_power_well skl_power_wells[] = {
 		.domains = SKL_DISPLAY_DC_OFF_POWER_DOMAINS,
 		.ops = &gen9_dc_off_power_well_ops,
 		.id = SKL_DISP_PW_DC_OFF,
+		.supports_atomic_ctx = true,
 	},
 	{
 		.name = "power well 2",
@@ -2168,6 +2311,7 @@  static struct i915_power_well bxt_power_wells[] = {
 		.domains = BXT_DISPLAY_DC_OFF_POWER_DOMAINS,
 		.ops = &gen9_dc_off_power_well_ops,
 		.id = SKL_DISP_PW_DC_OFF,
+		.supports_atomic_ctx = true,
 	},
 	{
 		.name = "power well 2",
@@ -2223,6 +2367,7 @@  static struct i915_power_well glk_power_wells[] = {
 		.domains = GLK_DISPLAY_DC_OFF_POWER_DOMAINS,
 		.ops = &gen9_dc_off_power_well_ops,
 		.id = SKL_DISP_PW_DC_OFF,
+		.supports_atomic_ctx = true,
 	},
 	{
 		.name = "power well 2",
@@ -2347,6 +2492,7 @@  static struct i915_power_well cnl_power_wells[] = {
 		.domains = CNL_DISPLAY_DC_OFF_POWER_DOMAINS,
 		.ops = &gen9_dc_off_power_well_ops,
 		.id = SKL_DISP_PW_DC_OFF,
+		.supports_atomic_ctx = true,
 	},
 	{
 		.name = "power well 2",
@@ -2475,6 +2621,7 @@  static void assert_power_well_ids_unique(struct drm_i915_private *dev_priv)
 int intel_power_domains_init(struct drm_i915_private *dev_priv)
 {
 	struct i915_power_domains *power_domains = &dev_priv->power_domains;
+	struct i915_power_well *power_well;
 
 	i915_modparams.disable_power_well =
 		sanitize_disable_power_well_option(dev_priv,
@@ -2512,6 +2659,10 @@  int intel_power_domains_init(struct drm_i915_private *dev_priv)
 		set_power_wells(power_domains, i9xx_always_on_power_well);
 	}
 
+	for_each_power_well(dev_priv, power_well)
+		if (power_well->supports_atomic_ctx)
+			spin_lock_init(&power_well->lock);
+
 	assert_power_well_ids_unique(dev_priv);
 
 	return 0;
@@ -2559,9 +2710,14 @@  static void intel_power_domains_sync_hw(struct drm_i915_private *dev_priv)
 
 	mutex_lock(&power_domains->lock);
 	for_each_power_well(dev_priv, power_well) {
+		unsigned long flags = 0;
+
+		power_well_lock(power_well, flags);
+
 		power_well->ops->sync_hw(dev_priv, power_well);
 		power_well->hw_enabled = power_well->ops->is_enabled(dev_priv,
 								     power_well);
+		power_well_unlock(power_well, flags);
 	}
 	mutex_unlock(&power_domains->lock);
 }
@@ -3034,16 +3190,18 @@  void intel_power_domains_suspend(struct drm_i915_private *dev_priv)
 		bxt_display_core_uninit(dev_priv);
 }
 
-static void intel_power_domains_dump_info(struct drm_i915_private *dev_priv)
+static void intel_power_domains_dump_info(struct drm_i915_private *dev_priv,
+					  const int *power_well_use)
 {
 	struct i915_power_domains *power_domains = &dev_priv->power_domains;
 	struct i915_power_well *power_well;
+	int i = 0;
 
 	for_each_power_well(dev_priv, power_well) {
 		enum intel_display_power_domain domain;
 
 		DRM_DEBUG_DRIVER("%-25s %d\n",
-				 power_well->name, power_well->count);
+				 power_well->name, power_well_use[i++]);
 
 		for_each_power_domain(domain, power_well->domains)
 			DRM_DEBUG_DRIVER("  %-23s %d\n",
@@ -3067,6 +3225,7 @@  void intel_power_domains_verify_state(struct drm_i915_private *dev_priv)
 	struct i915_power_domains *power_domains = &dev_priv->power_domains;
 	struct i915_power_well *power_well;
 	bool dump_domain_info;
+	int power_well_use[dev_priv->power_domains.power_well_count];
 
 	mutex_lock(&power_domains->lock);
 
@@ -3075,6 +3234,16 @@  void intel_power_domains_verify_state(struct drm_i915_private *dev_priv)
 		enum intel_display_power_domain domain;
 		int domains_count;
 		bool enabled;
+		int well_count, i = 0;
+		unsigned long flags = 0;
+
+
+		power_well_lock(power_well, flags);
+		well_count = power_well->count;
+		enabled = power_well->ops->is_enabled(dev_priv, power_well);
+		power_well_unlock(power_well, flags);
+
+		power_well_use[i++] = well_count;
 
 		/*
 		 * Power wells not belonging to any domain (like the MISC_IO
@@ -3084,20 +3253,19 @@  void intel_power_domains_verify_state(struct drm_i915_private *dev_priv)
 		if (!power_well->domains)
 			continue;
 
-		enabled = power_well->ops->is_enabled(dev_priv, power_well);
-		if ((power_well->count || power_well->always_on) != enabled)
+
+		if ((well_count || power_well->always_on) != enabled)
 			DRM_ERROR("power well %s state mismatch (refcount %d/enabled %d)",
-				  power_well->name, power_well->count, enabled);
+				  power_well->name, well_count, enabled);
 
 		domains_count = 0;
 		for_each_power_domain(domain, power_well->domains)
 			domains_count += atomic_read(&power_domains->domain_use_count[domain]);
 
-		if (power_well->count != domains_count) {
+		if (well_count != domains_count) {
 			DRM_ERROR("power well %s refcount/domain refcount mismatch "
 				  "(refcount %d/domains refcount %d)\n",
-				  power_well->name, power_well->count,
-				  domains_count);
+				  power_well->name, well_count, domains_count);
 			dump_domain_info = true;
 		}
 	}
@@ -3106,7 +3274,7 @@  void intel_power_domains_verify_state(struct drm_i915_private *dev_priv)
 		static bool dumped;
 
 		if (!dumped) {
-			intel_power_domains_dump_info(dev_priv);
+			intel_power_domains_dump_info(dev_priv, power_well_use);
 			dumped = true;
 		}
 	}