From b4b55cda587442477a3a9f0669e26bba4b7800c0 Mon Sep 17 00:00:00 2001 From: Jiang Liu Date: Thu, 5 Feb 2015 13:44:47 +0800 Subject: 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 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 Signed-off-by: Rafael J. Wysocki --- arch/x86/pci/common.c | 34 ++++++++++++++++++++++++++++------ 1 file changed, 28 insertions(+), 6 deletions(-) (limited to 'arch/x86/pci/common.c') 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) -- cgit v1.2.3