[PATCH 5/5] PCI / PM: Make PCIe PME interrupts wake up from suspend-to-idle

Rafael J. Wysocki
2014-08-05T15:10:59Z

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

To make PCIe PME interrupts wake up the system from suspend to idle,
make the PME driver use enable_irq_wake() on the IRQ during system
suspend (if there are any wakeup devices below the given PCIe port)
without disabling PME interrupts. This way, an interrupt will still
trigger if a wakeup event happens and the system will be woken up (or
system suspend in progress will be aborted) by means of the new
mechanics introduced previously.

This change allows Wake-on-LAN to be used for wakeup from
suspend-to-idle on my MSI Wind tesbed netbook.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/pci/pcie/pme.c | 61 ++++++++++++++++++++++++++++++++++++++++---------
1 file changed, 51 insertions(+), 10 deletions(-)

Index: linux-pm/drivers/pci/pcie/pme.c
===================================================================
--- linux-pm.orig/drivers/pci/pcie/pme.c
+++ linux-pm/drivers/pci/pcie/pme.c
@@ -41,11 +41,17 @@ static int __init pcie_pme_setup(char *s
}
__setup("pcie_pme=", pcie_pme_setup);

+enum pme_suspend_level {
+ PME_SUSPEND_NONE = 0,
+ PME_SUSPEND_WAKEUP,
+ PME_SUSPEND_NOIRQ,
+};
+
struct pcie_pme_service_data {
spinlock_t lock;
struct pcie_device *srv;
struct work_struct work;
- bool noirq; /* Don't enable the PME interrupt used by this service. */
+ enum pme_suspend_level suspend_level;
};

/**
@@ -223,7 +229,7 @@ static void pcie_pme_work_fn(struct work
spin_lock_irq(&data->lock);

for (;;) {
- if (data->noirq)
+ if (data->suspend_level != PME_SUSPEND_NONE)
break;

pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
@@ -250,7 +256,7 @@ static void pcie_pme_work_fn(struct work
spin_lock_irq(&data->lock);
}

- if (!data->noirq)
+ if (data->suspend_level == PME_SUSPEND_NONE)
pcie_pme_interrupt_enable(port, true);

spin_unlock_irq(&data->lock);
@@ -367,6 +373,21 @@ static int pcie_pme_probe(struct pcie_de
return ret;
}

+static bool pcie_pme_check_wakeup(struct pci_bus *bus)
+{
+ struct pci_dev *dev;
+
+ if (!bus)
+ return false;
+
+ list_for_each_entry(dev, &bus->devices, bus_list)
+ if (device_may_wakeup(&dev->dev)
+ || pcie_pme_check_wakeup(dev->subordinate))
+ return true;
+
+ return false;
+}
+
/**
* pcie_pme_suspend - Suspend PCIe PME service device.
* @srv: PCIe service device to suspend.
@@ -375,11 +396,26 @@ static int pcie_pme_suspend(struct pcie_
{
struct pcie_pme_service_data *data = get_service_data(srv);
struct pci_dev *port = srv->port;
+ bool wakeup;

+ if (device_may_wakeup(&port->dev)) {
+ wakeup = true;
+ } else {
+ down_read(&pci_bus_sem);
+ wakeup = pcie_pme_check_wakeup(port->subordinate);
+ up_read(&pci_bus_sem);
+ }
spin_lock_irq(&data->lock);
- pcie_pme_interrupt_enable(port, false);
- pcie_clear_root_pme_status(port);
- data->noirq = true;
+ if (wakeup) {
+ enable_irq_wake(srv->irq);
+ data->suspend_level = PME_SUSPEND_WAKEUP;
+ } else {
+ struct pci_dev *port = srv->port;
+
+ pcie_pme_interrupt_enable(port, false);
+ pcie_clear_root_pme_status(port);
+ data->suspend_level = PME_SUSPEND_NOIRQ;
+ }
spin_unlock_irq(&data->lock);

synchronize_irq(srv->irq);
@@ -394,12 +430,17 @@ static int pcie_pme_suspend(struct pcie_
static int pcie_pme_resume(struct pcie_device *srv)
{
struct pcie_pme_service_data *data = get_service_data(srv);
- struct pci_dev *port = srv->port;

spin_lock_irq(&data->lock);
- data->noirq = false;
- pcie_clear_root_pme_status(port);
- pcie_pme_interrupt_enable(port, true);
+ if (data->suspend_level == PME_SUSPEND_NOIRQ) {
+ struct pci_dev *port = srv->port;
+
+ pcie_clear_root_pme_status(port);
+ pcie_pme_interrupt_enable(port, true);
+ } else {
+ disable_irq_wake(srv->irq);
+ }
+ data->suspend_level = PME_SUSPEND_NONE;
spin_unlock_irq(&data->lock);

return 0;