[PATCH v8 0/4] Allow USB devices to remain runtime-suspended when sleeping

[PATCH v8 0/4] Allow USB devices to remain runtime-suspended when sleeping

[Tomeu Vizoso]

Hi,

this is v8 of an attempt to make it easier for devices to remain in
runtime PM when the system goes to sleep, mainly to reduce the time
spent resuming devices.

For this, we interpret the absence of all PM callback implementations as
it being safe to do direct_complete, so their ancestors aren't prevented
from remaining runtime-suspended.

Additionally, the prepare() callback of USB devices will return 1 if
runtime PM is enabled and the current wakeup settings are correct.

With these changes, a uvcvideo device (for example) stays in runtime
suspend when the system goes to sleep and is left in that state when the
system resumes, not delaying it unnecessarily.

Thanks,

Tomeu

Changes in v8:
- Add device_is_bound()
- Add dev_pm_domain_set() and update code to use it
- Move no_pm_callbacks field into CONFIG_PM_SLEEP
- Call device_check_pm_callbacks only after a device is bound or unbound

Changes in v7:
- Reduce indentation by adding a label in device_prepare()

Changes in v6:
- Add stub for !CONFIG_PM.
- Move implementation of device_check_pm_callbacks to power/main.c as it
  doesn't belong to CONFIG_PM_SLEEP.
- Take dev->power.lock before modifying flag.

Changes in v5:
- Check for all dev_pm_ops instances associated to a device, updating a
  no_pm_callbacks flag at the times when that could change.

Tomeu Vizoso (4):
  device core: add device_is_bound()
  PM / Domains: add setter for dev.pm_domain
  PM / sleep: Go direct_complete if driver has no callbacks
  USB / PM: Allow USB devices to remain runtime-suspended when sleeping

 arch/arm/mach-omap2/omap_device.c |  7 ++++---
 drivers/acpi/acpi_lpss.c          |  5 +++--
 drivers/acpi/device_pm.c          |  5 +++--
 drivers/base/dd.c                 | 12 ++++++++++--
 drivers/base/power/clock_ops.c    |  5 +++--
 drivers/base/power/common.c       |  8 ++++++++
 drivers/base/power/domain.c       |  6 ++++--
 drivers/base/power/main.c         | 33 +++++++++++++++++++++++++++++++++
 drivers/base/power/power.h        |  6 ++++++
 drivers/gpu/vga/vga_switcheroo.c  | 10 +++++-----
 drivers/misc/mei/pci-me.c         |  5 +++--
 drivers/misc/mei/pci-txe.c        |  5 +++--
 drivers/usb/core/port.c           |  6 ++++++
 drivers/usb/core/usb.c            | 11 ++++++++++-
 include/linux/device.h            |  2 ++
 include/linux/pm.h                |  1 +
 include/linux/pm_domain.h         |  3 +++
 17 files changed, 107 insertions(+), 23 deletions(-)

-- 
2.4.3

[PATCH v8 2/4] PM / Domains: add setter for dev.pm_domain

[Tomeu Vizoso]

Adds a function that sets the pointer to dev_pm_domain in struct device
and that warns if the device has already finished probing. The reason
why we want to enforce that is because in the general case that can
cause problems and also that we can simplify code quite a bit if we can
always assume that.

This patch also changes all current code that directly sets the
dev.pm_domain pointer.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
---

Changes in v8:
- Add dev_pm_domain_set() and update code to use it

 arch/arm/mach-omap2/omap_device.c |  7 ++++---
 drivers/acpi/acpi_lpss.c          |  5 +++--
 drivers/acpi/device_pm.c          |  5 +++--
 drivers/base/power/clock_ops.c    |  5 +++--
 drivers/base/power/common.c       |  8 ++++++++
 drivers/base/power/domain.c       |  4 ++--
 drivers/gpu/vga/vga_switcheroo.c  | 10 +++++-----
 drivers/misc/mei/pci-me.c         |  5 +++--
 drivers/misc/mei/pci-txe.c        |  5 +++--
 include/linux/pm_domain.h         |  3 +++
 10 files changed, 37 insertions(+), 20 deletions(-)

diff --git a/arch/arm/mach-omap2/omap_device.c b/arch/arm/mach-omap2/omap_device.c
index 4cb8fd9f741f..204101d11632 100644
--- a/arch/arm/mach-omap2/omap_device.c
+++ b/arch/arm/mach-omap2/omap_device.c
@@ -32,6 +32,7 @@
 #include <linux/io.h>
 #include <linux/clk.h>
 #include <linux/clkdev.h>
+#include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
 #include <linux/of.h>
 #include <linux/notifier.h>
@@ -168,7 +169,7 @@ static int omap_device_build_from_dt(struct platform_device *pdev)
 			r->name = dev_name(&pdev->dev);
 	}
 
-	pdev->dev.pm_domain = &omap_device_pm_domain;
+	dev_pm_domain_set(&pdev->dev, &omap_device_pm_domain);
 
 	if (device_active) {
 		omap_device_enable(pdev);
@@ -180,7 +181,7 @@ odbfd_exit1:
 odbfd_exit:
 	/* if data/we are at fault.. load up a fail handler */
 	if (ret)
-		pdev->dev.pm_domain = &omap_device_fail_pm_domain;
+		dev_pm_domain_set(&pdev->dev, &omap_device_fail_pm_domain);
 
 	return ret;
 }
@@ -701,7 +702,7 @@ int omap_device_register(struct platform_device *pdev)
 {
 	pr_debug("omap_device: %s: registering\n", pdev->name);
 
-	pdev->dev.pm_domain = &omap_device_pm_domain;
+	dev_pm_domain_set(&pdev->dev, &omap_device_pm_domain);
 	return platform_device_add(pdev);
 }
 
diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
index f51bd0d0bc17..cc6e1abc69b3 100644
--- a/drivers/acpi/acpi_lpss.c
+++ b/drivers/acpi/acpi_lpss.c
@@ -17,6 +17,7 @@
 #include <linux/io.h>
 #include <linux/platform_device.h>
 #include <linux/platform_data/clk-lpss.h>
+#include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
 #include <linux/delay.h>
 
@@ -706,7 +707,7 @@ static int acpi_lpss_platform_notify(struct notifier_block *nb,
 
 	switch (action) {
 	case BUS_NOTIFY_ADD_DEVICE:
-		pdev->dev.pm_domain = &acpi_lpss_pm_domain;
+		dev_pm_domain_set(&pdev->dev, &acpi_lpss_pm_domain);
 		if (pdata->dev_desc->flags & LPSS_LTR)
 			return sysfs_create_group(&pdev->dev.kobj,
 						  &lpss_attr_group);
@@ -714,7 +715,7 @@ static int acpi_lpss_platform_notify(struct notifier_block *nb,
 	case BUS_NOTIFY_DEL_DEVICE:
 		if (pdata->dev_desc->flags & LPSS_LTR)
 			sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group);
-		pdev->dev.pm_domain = NULL;
+		dev_pm_domain_set(&pdev->dev, NULL);
 		break;
 	default:
 		break;
diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index 4806b7f856c4..8c5955bf9bbf 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -22,6 +22,7 @@
 #include <linux/export.h>
 #include <linux/mutex.h>
 #include <linux/pm_qos.h>
+#include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
 
 #include "internal.h"
@@ -1076,7 +1077,7 @@ static void acpi_dev_pm_detach(struct device *dev, bool power_off)
 	struct acpi_device *adev = ACPI_COMPANION(dev);
 
 	if (adev && dev->pm_domain == &acpi_general_pm_domain) {
-		dev->pm_domain = NULL;
+		dev_pm_domain_set(dev, NULL);
 		acpi_remove_pm_notifier(adev);
 		if (power_off) {
 			/*
@@ -1128,7 +1129,7 @@ int acpi_dev_pm_attach(struct device *dev, bool power_on)
 		return -EBUSY;
 
 	acpi_add_pm_notifier(adev, dev, acpi_pm_notify_work_func);
-	dev->pm_domain = &acpi_general_pm_domain;
+	dev_pm_domain_set(dev, &acpi_general_pm_domain);
 	if (power_on) {
 		acpi_dev_pm_full_power(adev);
 		acpi_device_wakeup(adev, ACPI_STATE_S0, false);
diff --git a/drivers/base/power/clock_ops.c b/drivers/base/power/clock_ops.c
index 652b5a367c1f..e80fda6c03a9 100644
--- a/drivers/base/power/clock_ops.c
+++ b/drivers/base/power/clock_ops.c
@@ -15,6 +15,7 @@
 #include <linux/clkdev.h>
 #include <linux/slab.h>
 #include <linux/err.h>
+#include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
 
 #ifdef CONFIG_PM
@@ -346,7 +347,7 @@ static int pm_clk_notify(struct notifier_block *nb,
 		if (error)
 			break;
 
-		dev->pm_domain = clknb->pm_domain;
+		dev_pm_domain_set(dev, clknb->pm_domain);
 		if (clknb->con_ids[0]) {
 			for (con_id = clknb->con_ids; *con_id; con_id++)
 				pm_clk_add(dev, *con_id);
@@ -359,7 +360,7 @@ static int pm_clk_notify(struct notifier_block *nb,
 		if (dev->pm_domain != clknb->pm_domain)
 			break;
 
-		dev->pm_domain = NULL;
+		dev_pm_domain_set(dev, NULL);
 		pm_clk_destroy(dev);
 		break;
 	}
diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c
index f32b802b98f4..5d308aab22d6 100644
--- a/drivers/base/power/common.c
+++ b/drivers/base/power/common.c
@@ -128,3 +128,11 @@ void dev_pm_domain_detach(struct device *dev, bool power_off)
 		dev->pm_domain->detach(dev, power_off);
 }
 EXPORT_SYMBOL_GPL(dev_pm_domain_detach);
+
+void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd)
+{
+	WARN(device_is_bound(dev),
+	     "PM domains can only be changed for unbound devices\n");
+	dev->pm_domain = pd;
+}
+EXPORT_SYMBOL_GPL(dev_pm_domain_set);
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 16550c63d611..b75d02aa8d93 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1240,7 +1240,7 @@ static struct generic_pm_domain_data *genpd_alloc_dev_data(struct device *dev,
 	}
 
 	dev->power.subsys_data->domain_data = &gpd_data->base;
-	dev->pm_domain = &genpd->domain;
+	dev_pm_domain_set(dev, &genpd->domain);
 
 	spin_unlock_irq(&dev->power.lock);
 
@@ -1259,7 +1259,7 @@ static void genpd_free_dev_data(struct device *dev,
 {
 	spin_lock_irq(&dev->power.lock);
 
-	dev->pm_domain = NULL;
+	dev_pm_domain_set(dev, NULL);
 	dev->power.subsys_data->domain_data = NULL;
 
 	spin_unlock_irq(&dev->power.lock);
diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index 21060668fd25..2c3208ea6de4 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -665,17 +665,17 @@ int vga_switcheroo_init_domain_pm_ops(struct device *dev,
 		domain->ops.runtime_suspend = vga_switcheroo_runtime_suspend;
 		domain->ops.runtime_resume = vga_switcheroo_runtime_resume;
 
-		dev->pm_domain = domain;
+		dev_pm_domain_set(dev, domain);
 		return 0;
 	}
-	dev->pm_domain = NULL;
+	dev_pm_domain_set(dev, NULL);
 	return -EINVAL;
 }
 EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_ops);
 
 void vga_switcheroo_fini_domain_pm_ops(struct device *dev)
 {
-	dev->pm_domain = NULL;
+	dev_pm_domain_set(dev, NULL);
 }
 EXPORT_SYMBOL(vga_switcheroo_fini_domain_pm_ops);
 
@@ -719,10 +719,10 @@ vga_switcheroo_init_domain_pm_optimus_hdmi_audio(struct device *dev,
 		domain->ops.runtime_resume =
 			vga_switcheroo_runtime_resume_hdmi_audio;
 
-		dev->pm_domain = domain;
+		dev_pm_domain_set(dev, domain);
 		return 0;
 	}
-	dev->pm_domain = NULL;
+	dev_pm_domain_set(dev, NULL);
 	return -EINVAL;
 }
 EXPORT_SYMBOL(vga_switcheroo_init_domain_pm_optimus_hdmi_audio);
diff --git a/drivers/misc/mei/pci-me.c b/drivers/misc/mei/pci-me.c
index 27678d8154e0..75fc9c688df8 100644
--- a/drivers/misc/mei/pci-me.c
+++ b/drivers/misc/mei/pci-me.c
@@ -31,6 +31,7 @@
 #include <linux/jiffies.h>
 #include <linux/interrupt.h>
 
+#include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
 
 #include <linux/mei.h>
@@ -436,7 +437,7 @@ static inline void mei_me_set_pm_domain(struct mei_device *dev)
 		dev->pg_domain.ops.runtime_resume = mei_me_pm_runtime_resume;
 		dev->pg_domain.ops.runtime_idle = mei_me_pm_runtime_idle;
 
-		pdev->dev.pm_domain = &dev->pg_domain;
+		dev_pm_domain_set(&pdev->dev, &dev->pg_domain);
 	}
 }
 
@@ -448,7 +449,7 @@ static inline void mei_me_set_pm_domain(struct mei_device *dev)
 static inline void mei_me_unset_pm_domain(struct mei_device *dev)
 {
 	/* stop using pm callbacks if any */
-	dev->dev->pm_domain = NULL;
+	dev_pm_domain_set(dev->dev, NULL);
 }
 
 static const struct dev_pm_ops mei_me_pm_ops = {
diff --git a/drivers/misc/mei/pci-txe.c b/drivers/misc/mei/pci-txe.c
index 0882c0201907..71f8a7475717 100644
--- a/drivers/misc/mei/pci-txe.c
+++ b/drivers/misc/mei/pci-txe.c
@@ -27,6 +27,7 @@
 #include <linux/jiffies.h>
 #include <linux/interrupt.h>
 #include <linux/workqueue.h>
+#include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
 
 #include <linux/mei.h>
@@ -388,7 +389,7 @@ static inline void mei_txe_set_pm_domain(struct mei_device *dev)
 		dev->pg_domain.ops.runtime_resume = mei_txe_pm_runtime_resume;
 		dev->pg_domain.ops.runtime_idle = mei_txe_pm_runtime_idle;
 
-		pdev->dev.pm_domain = &dev->pg_domain;
+		dev_pm_domain_set(&pdev->dev, &dev->pg_domain);
 	}
 }
 
@@ -400,7 +401,7 @@ static inline void mei_txe_set_pm_domain(struct mei_device *dev)
 static inline void mei_txe_unset_pm_domain(struct mei_device *dev)
 {
 	/* stop using pm callbacks if any */
-	dev->dev->pm_domain = NULL;
+	dev_pm_domain_set(dev->dev, NULL);
 }
 
 static const struct dev_pm_ops mei_txe_pm_ops = {
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index b1cf7e797892..4ae4b14fb7b4 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -306,12 +306,15 @@ static inline int of_genpd_add_provider_onecell(struct device_node *np,
 #ifdef CONFIG_PM
 extern int dev_pm_domain_attach(struct device *dev, bool power_on);
 extern void dev_pm_domain_detach(struct device *dev, bool power_off);
+extern void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd);
 #else
 static inline int dev_pm_domain_attach(struct device *dev, bool power_on)
 {
 	return -ENODEV;
 }
 static inline void dev_pm_domain_detach(struct device *dev, bool power_off) {}
+static inline void dev_pm_domain_set(struct device *dev,
+				     struct dev_pm_domain *pd) {}
 #endif
 
 #endif /* _LINUX_PM_DOMAIN_H */
-- 
2.4.3

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