Merge branches 'pm-pci' and 'acpi-pci'

* pm-pci:
  PCI / PM: Update runtime PM documentation for PCI devices

* acpi-pci:
  ACPI / PCI: Remove duplicated penalty on SCI IRQ
  ACPI, PCI, irq: Do not share PCI IRQ with ISA IRQ

Documentation/power/pci.txt

@@ -979,20 +979,45 @@ every time right after the runtime_resume() callback has returned
 (alternatively, the runtime_suspend() callback will have to check if the
 device should really be suspended and return -EAGAIN if that is not the case).
 
-The runtime PM of PCI devices is disabled by default.  It is also blocked by
-pci_pm_init() that runs the pm_runtime_forbid() helper function.  If a PCI
-driver implements the runtime PM callbacks and intends to use the runtime PM
-framework provided by the PM core and the PCI subsystem, it should enable this
-feature by executing the pm_runtime_enable() helper function.  However, the
-driver should not call the pm_runtime_allow() helper function unblocking
-the runtime PM of the device.  Instead, it should allow user space or some
-platform-specific code to do that (user space can do it via sysfs), although
-once it has called pm_runtime_enable(), it must be prepared to handle the
+The runtime PM of PCI devices is enabled by default by the PCI core.  PCI
+device drivers do not need to enable it and should not attempt to do so.
+However, it is blocked by pci_pm_init() that runs the pm_runtime_forbid()
+helper function.  In addition to that, the runtime PM usage counter of
+each PCI device is incremented by local_pci_probe() before executing the
+probe callback provided by the device's driver.
+
+If a PCI driver implements the runtime PM callbacks and intends to use the
+runtime PM framework provided by the PM core and the PCI subsystem, it needs
+to decrement the device's runtime PM usage counter in its probe callback
+function.  If it doesn't do that, the counter will always be different from
+zero for the device and it will never be runtime-suspended.  The simplest
+way to do that is by calling pm_runtime_put_noidle(), but if the driver
+wants to schedule an autosuspend right away, for example, it may call
+pm_runtime_put_autosuspend() instead for this purpose.  Generally, it
+just needs to call a function that decrements the devices usage counter
+from its probe routine to make runtime PM work for the device.
+
+It is important to remember that the driver's runtime_suspend() callback
+may be executed right after the usage counter has been decremented, because
+user space may already have cuased the pm_runtime_allow() helper function
+unblocking the runtime PM of the device to run via sysfs, so the driver must
+be prepared to cope with that.
+
+The driver itself should not call pm_runtime_allow(), though.  Instead, it
+should let user space or some platform-specific code do that (user space can
+do it via sysfs as stated above), but it must be prepared to handle the
 runtime PM of the device correctly as soon as pm_runtime_allow() is called
-(which may happen at any time).  [It also is possible that user space causes
-pm_runtime_allow() to be called via sysfs before the driver is loaded, so in
-fact the driver has to be prepared to handle the runtime PM of the device as
-soon as it calls pm_runtime_enable().]
+(which may happen at any time, even before the driver is loaded).
+
+When the driver's remove callback runs, it has to balance the decrementation
+of the device's runtime PM usage counter at the probe time.  For this reason,
+if it has decremented the counter in its probe callback, it must run
+pm_runtime_get_noresume() in its remove callback.  [Since the core carries
+out a runtime resume of the device and bumps up the device's usage counter
+before running the driver's remove callback, the runtime PM of the device
+is effectively disabled for the duration of the remove execution and all
+runtime PM helper functions incrementing the device's usage counter are
+then effectively equivalent to pm_runtime_get_noresume().]
 
 The runtime PM framework works by processing requests to suspend or resume
 devices, or to check if they are idle (in which cases it is reasonable to

drivers/acpi/pci_irq.c

@@ -372,6 +372,7 @@ static int acpi_isa_register_gsi(struct pci_dev *dev)
 
 	/* Interrupt Line values above 0xF are forbidden */
 	if (dev->irq > 0 && (dev->irq <= 0xF) &&
+	    acpi_isa_irq_available(dev->irq) &&
 	    (acpi_isa_irq_to_gsi(dev->irq, &dev_gsi) == 0)) {
 		dev_warn(&dev->dev, "PCI INT %c: no GSI - using ISA IRQ %d\n",
 			 pin_name(dev->pin), dev->irq);

drivers/acpi/pci_link.c

@@ -498,8 +498,7 @@ int __init acpi_irq_penalty_init(void)
 			    PIRQ_PENALTY_PCI_POSSIBLE;
 		}
 	}
-	/* Add a penalty for the SCI */
-	acpi_irq_penalty[acpi_gbl_FADT.sci_interrupt] += PIRQ_PENALTY_PCI_USING;
+
 	return 0;
 }
 
@@ -553,6 +552,13 @@ static int acpi_pci_link_allocate(struct acpi_pci_link *link)
 				irq = link->irq.possible[i];
 		}
 	}
+	if (acpi_irq_penalty[irq] >= PIRQ_PENALTY_ISA_ALWAYS) {
+		printk(KERN_ERR PREFIX "No IRQ available for %s [%s]. "
+			    "Try pci=noacpi or acpi=off\n",
+			    acpi_device_name(link->device),
+			    acpi_device_bid(link->device));
+		return -ENODEV;
+	}
 
 	/* Attempt to enable the link device at this IRQ. */
 	if (acpi_pci_link_set(link, irq)) {
@@ -821,6 +827,12 @@ void acpi_penalize_isa_irq(int irq, int active)
 	}
 }
 
+bool acpi_isa_irq_available(int irq)
+{
+	return irq >= 0 && (irq >= ARRAY_SIZE(acpi_irq_penalty) ||
+			    acpi_irq_penalty[irq] < PIRQ_PENALTY_ISA_ALWAYS);
+}
+
 /*
  * Penalize IRQ used by ACPI SCI. If ACPI SCI pin attributes conflict with
  * PCI IRQ attributes, mark ACPI SCI as ISA_ALWAYS so it won't be use for

drivers/pci/pci-driver.c

@@ -299,9 +299,10 @@ static long local_pci_probe(void *_ddi)
 	 * Unbound PCI devices are always put in D0, regardless of
 	 * runtime PM status.  During probe, the device is set to
 	 * active and the usage count is incremented.  If the driver
-	 * supports runtime PM, it should call pm_runtime_put_noidle()
-	 * in its probe routine and pm_runtime_get_noresume() in its
-	 * remove routine.
+	 * supports runtime PM, it should call pm_runtime_put_noidle(),
+	 * or any other runtime PM helper function decrementing the usage
+	 * count, in its probe routine and pm_runtime_get_noresume() in
+	 * its remove routine.
 	 */
 	pm_runtime_get_sync(dev);
 	pci_dev->driver = pci_drv;

include/linux/acpi.h

@@ -217,6 +217,7 @@ struct pci_dev;
 
 int acpi_pci_irq_enable (struct pci_dev *dev);
 void acpi_penalize_isa_irq(int irq, int active);
+bool acpi_isa_irq_available(int irq);
 void acpi_penalize_sci_irq(int irq, int trigger, int polarity);
 void acpi_pci_irq_disable (struct pci_dev *dev);