From 7612b3b28c0b900dcbcdf5e9b9747cc20a1e2455 Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Tue, 1 Aug 2017 03:11:52 -0400 Subject: [PATCH] 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: fad214b0aa72 ("PCI: pciehp: Process all hotplug events before looking for new ones") Signed-off-by: Keith Busch [bhelgaas: changelog, pull test out and add comment] Signed-off-by: Bjorn Helgaas Cc: Mayurkumar Patel Cc: stable@vger.kernel.org # 4.9+ --- drivers/pci/hotplug/pciehp_hpc.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index 026830a138ae..e5d5ce9e3010 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -586,6 +586,14 @@ static irqreturn_t pciehp_isr(int irq, void *dev_id) events = status & (PCI_EXP_SLTSTA_ABP | PCI_EXP_SLTSTA_PFD | PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_CC | 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) return IRQ_NONE;