[Bugfix] x86, irq, PCI: Keep IRQ assignment for PCI devices during suspend/hibernation

Jiang Liu
2014-08-08T06:05:07Z

Now IOAPIC driver dynamically allocates IRQ numbers for IOAPIC pins.
We need to keep IRQ assignment for PCI devices during suspend/hibernation,
otherwise it may cause failure of suspend/hibernation due to:
1) Device driver calls pci_enable_device() to allocate an IRQ number
and register interrupt handler on the returned IRQ.
2) Device driver's suspend callback calls pci_disable_device() and
release assigned IRQ in turn.
3) Device driver's resume callback calls pci_enable_device() to
allocate IRQ number again. A different IRQ number may be assigned
by IOAPIC driver this time.
4) Now the hardware delivers interrupt to the new IRQ but interrupt
handler is still registered against the old IRQ, so it breaks
suspend/hibernation.

To fix this issue, we keep IRQ assignment during suspend/hibernation.
Flag pci_dev.dev.power.is_prepared is used to detect that
pci_disable_device() is called during suspend/hibernation.

Reported-and-Tested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
---
Hi Ingo,
Could you please help to apply this patch onto
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-apic-for-linus?
It fixes the suspend/hibernation failure reported by Borislav.
Thanks!
Gerry
---
arch/x86/pci/intel_mid_pci.c | 2 +-
arch/x86/pci/irq.c | 3 ++-
drivers/acpi/pci_irq.c | 4 ++++
3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/x86/pci/intel_mid_pci.c b/arch/x86/pci/intel_mid_pci.c
index 09fece368592..3865116c51fb 100644
--- a/arch/x86/pci/intel_mid_pci.c
+++ b/arch/x86/pci/intel_mid_pci.c
@@ -229,7 +229,7 @@ static int intel_mid_pci_irq_enable(struct pci_dev *dev)

static void intel_mid_pci_irq_disable(struct pci_dev *dev)
{
- if (dev->irq > 0)
+ if (!dev->dev.power.is_prepared && dev->irq > 0)
mp_unmap_irq(dev->irq);
}

diff --git a/arch/x86/pci/irq.c b/arch/x86/pci/irq.c
index 748cfe8ab322..bc1a2c341891 100644
--- a/arch/x86/pci/irq.c
+++ b/arch/x86/pci/irq.c
@@ -1256,7 +1256,8 @@ static int pirq_enable_irq(struct pci_dev *dev)

static void pirq_disable_irq(struct pci_dev *dev)
{
- if (io_apic_assign_pci_irqs && dev->irq) {
+ if (io_apic_assign_pci_irqs && !dev->dev.power.is_prepared &&
+ dev->irq) {
mp_unmap_irq(dev->irq);
dev->irq = 0;
}
diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
index 6ba463ceccc6..c96887d5289e 100644
--- a/drivers/acpi/pci_irq.c
+++ b/drivers/acpi/pci_irq.c
@@ -481,6 +481,10 @@ void acpi_pci_irq_disable(struct pci_dev *dev)
if (!pin)
return;

+ /* Keep IOAPIC pin configuration when suspending */
+ if (dev->dev.power.is_prepared)
+ return;
+
entry = acpi_pci_irq_lookup(dev, pin);
if (!entry)
return;
--
1.7.10.4