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PCI: pciehp: Report power fault only once until we clear it 

When a power fault occurs, the power controller sets Power Fault Detected
in the Slot Status register, and pciehp_isr() queues an INT_POWER_FAULT
event to handle it.

It also clears Power Fault Detected, but since nothing has yet changed to
correct the power fault, the power controller will likely set it again
immediately, which may cause an infinite loop when pcie_isr() rechecks
Slot Status.

Fix that by masking off Power Fault Detected from new events if the driver
hasn't seen the power fault clear from the previous handling attempt.

Fixes: fad214b0aa ("PCI: pciehp: Process all hotplug events before looking for new ones")
Signed-off-by: Keith Busch <keith.busch@intel.com>
[bhelgaas: changelog, pull test out and add comment]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Mayurkumar Patel <mayurkumar.patel@intel.com>
Cc: stable@vger.kernel.org	# 4.9+
This commit is contained in:
Keith Busch 2017-08-01 03:11:52 -04:00 committed by Bjorn Helgaas
parent 48b79a1450
commit 7612b3b28c
1 changed files with 8 additions and 0 deletions
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8
drivers/pci/hotplug/pciehp_hpc.c
View File

@ -586,6 +586,14 @@ static irqreturn_t pciehp_isr(int irq, void *dev_id)
events = status & (PCI_EXP_SLTSTA_ABP | PCI_EXP_SLTSTA_PFD | events = status & (PCI_EXP_SLTSTA_ABP | PCI_EXP_SLTSTA_PFD |
PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_CC | PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_CC |
PCI_EXP_SLTSTA_DLLSC); PCI_EXP_SLTSTA_DLLSC);
/*
* If we've already reported a power fault, don't report it again
* until we've done something to handle it.
*/
if (ctrl->power_fault_detected)
events &= ~PCI_EXP_SLTSTA_PFD;
if (!events) if (!events)
return IRQ_NONE; return IRQ_NONE;