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authorJiang Liu <jiang.liu@linux.intel.com>2015-02-05 08:44:47 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-02-05 17:09:26 +0300
commitb4b55cda587442477a3a9f0669e26bba4b7800c0 (patch)
treee60388e241582d3d9a04e11e230a7805e9b5969b /arch/x86/pci/common.c
parent593669c2ac0fe18baee04a3cd5539a148aa48574 (diff)
downloadlinux-b4b55cda587442477a3a9f0669e26bba4b7800c0.tar.xz
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 c03b3b0738a5 ("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 3eec595235c1 ("x86, irq, PCI: Keep IRQ assignment for PCI devices during suspend/hibernation") and 9eabc99a635a ("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 cffe0a2b5a34 ("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: Jiang Liu <jiang.liu@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'arch/x86/pci/common.c')
-rw-r--r--arch/x86/pci/common.c34
1 files changed, 28 insertions, 6 deletions
diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
index 7b20bccf3648..ff1f0afa5ed1 100644
--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -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)