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Commit b4b55cda authored by Jiang Liu's avatar Jiang Liu Committed by Rafael J. Wysocki
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x86/PCI: Refine the way to release PCI IRQ resources 

Some PCI device drivers assume that pci_dev->irq won't change after
calling pci_disable_device() and pci_enable_device() during suspend and
resume.

Commit c03b3b07 ("x86, irq, mpparse: Release IOAPIC pin when
PCI device is disabled") frees PCI IRQ resources when pci_disable_device()
is called and reallocate IRQ resources when pci_enable_device() is
called again. This breaks above assumption. So commit 3eec5952
("x86, irq, PCI: Keep IRQ assignment for PCI devices during
suspend/hibernation") and 9eabc99a ("x86, irq, PCI: Keep IRQ
assignment for runtime power management") fix the issue by avoiding
freeing/reallocating IRQ resources during PCI device suspend/resume.
They achieve this by checking dev.power.is_prepared and
dev.power.runtime_status.  PM maintainer, Rafael, then pointed out that
it's really an ugly fix which leaking PM internal state information to
IRQ subsystem.

Recently David Vrabel <david.vrabel@citrix.com> also reports an
regression in pciback driver caused by commit cffe0a2b ("x86, irq:
Keep balance of IOAPIC pin reference count"). Please refer to:
http://lkml.org/lkml/2015/1/14/546



So this patch refine the way to release PCI IRQ resources. Instead of
releasing PCI IRQ resources in pci_disable_device()/
pcibios_disable_device(), we now release it at driver unbinding
notification BUS_NOTIFY_UNBOUND_DRIVER. In other word, we only release
PCI IRQ resources when there's no driver bound to the PCI device, and
it keeps the assumption that pci_dev->irq won't through multiple
invocation of pci_enable_device()/pci_disable_device().

Signed-off-by: default avatarJiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 593669c2

arch/x86/include/asm/pci_x86.h

+0 −2
Original line number Diff line number Diff line
@@ -93,8 +93,6 @@ extern raw_spinlock_t pci_config_lock; 
extern int (*pcibios_enable_irq)(struct pci_dev *dev);

extern void (*pcibios_disable_irq)(struct pci_dev *dev);



extern bool mp_should_keep_irq(struct device *dev);



struct pci_raw_ops {

	int (*read)(unsigned int domain, unsigned int bus, unsigned int devfn,

						int reg, int len, u32 *val);

arch/x86/pci/common.c

+28 −6
Original line number Diff line number Diff line
@@ -497,6 +497,31 @@ void __init pcibios_set_cache_line_size(void) 
	}

}



/*

 * Some device drivers assume dev->irq won't change after calling

 * pci_disable_device(). So delay releasing of IRQ resource to driver

 * unbinding time. Otherwise it will break PM subsystem and drivers

 * like xen-pciback etc.

 */

static int pci_irq_notifier(struct notifier_block *nb, unsigned long action,

			    void *data)

{

	struct pci_dev *dev = to_pci_dev(data);



	if (action != BUS_NOTIFY_UNBOUND_DRIVER)

		return NOTIFY_DONE;



	if (pcibios_disable_irq)

		pcibios_disable_irq(dev);



	return NOTIFY_OK;

}



static struct notifier_block pci_irq_nb = {

	.notifier_call = pci_irq_notifier,

	.priority = INT_MIN,

};



int __init pcibios_init(void)

{

	if (!raw_pci_ops) {
@@ -509,6 +534,9 @@ int __init pcibios_init(void) 


	if (pci_bf_sort >= pci_force_bf)

		pci_sort_breadthfirst();



	bus_register_notifier(&pci_bus_type, &pci_irq_nb);



	return 0;

}
@@ -667,12 +695,6 @@ int pcibios_enable_device(struct pci_dev *dev, int mask) 
	return 0;

}



void pcibios_disable_device (struct pci_dev *dev)

{

	if (!pci_dev_msi_enabled(dev) && pcibios_disable_irq)

		pcibios_disable_irq(dev);

}



int pci_ext_cfg_avail(void)

{

	if (raw_pci_ext_ops)

arch/x86/pci/intel_mid_pci.c

+2 −2
Original line number Diff line number Diff line
@@ -234,10 +234,10 @@ static int intel_mid_pci_irq_enable(struct pci_dev *dev) 


static void intel_mid_pci_irq_disable(struct pci_dev *dev)

{

	if (!mp_should_keep_irq(&dev->dev) && dev->irq_managed &&

	    dev->irq > 0) {

	if (dev->irq_managed && dev->irq > 0) {

		mp_unmap_irq(dev->irq);

		dev->irq_managed = 0;

		dev->irq = 0;

	}

}

arch/x86/pci/irq.c

+1 −14
Original line number Diff line number Diff line
@@ -1256,22 +1256,9 @@ static int pirq_enable_irq(struct pci_dev *dev) 
	return 0;

}



bool mp_should_keep_irq(struct device *dev)

{

	if (dev->power.is_prepared)

		return true;

#ifdef CONFIG_PM

	if (dev->power.runtime_status == RPM_SUSPENDING)

		return true;

#endif



	return false;

}



static void pirq_disable_irq(struct pci_dev *dev)

{

	if (io_apic_assign_pci_irqs && !mp_should_keep_irq(&dev->dev) &&

	    dev->irq_managed && dev->irq) {

	if (io_apic_assign_pci_irqs && dev->irq_managed && dev->irq) {

		mp_unmap_irq(dev->irq);

		dev->irq = 0;

		dev->irq_managed = 0;

drivers/acpi/pci_irq.c

+1 −8
Original line number Diff line number Diff line
@@ -485,14 +485,6 @@ void acpi_pci_irq_disable(struct pci_dev *dev) 
	if (!pin || !dev->irq_managed || dev->irq <= 0)

		return;



	/* Keep IOAPIC pin configuration when suspending */

	if (dev->dev.power.is_prepared)

		return;

#ifdef	CONFIG_PM

	if (dev->dev.power.runtime_status == RPM_SUSPENDING)

		return;

#endif



	entry = acpi_pci_irq_lookup(dev, pin);

	if (!entry)

		return;
@@ -513,5 +505,6 @@ void acpi_pci_irq_disable(struct pci_dev *dev) 
	if (gsi >= 0) {

		acpi_unregister_gsi(gsi);

		dev->irq_managed = 0;

		dev->irq = 0;

	}

}