Date: Wed, 27 Mar 2013 06:59:59 -0400 From: Peter Hurley Subject: firewire: ohci: Check LPS before register access on pci removal A pci device can be removed while in its suspended state. If the ohci host controller is suspended, the PHY is also in low-power mode and LPS is disabled. If LPS is disabled, most of the host registers aren't accessible, including IntMaskClear. Furthermore, access to these registers when LPS is disabled can cause hard lockups on some hardware. Since interrupts are already disabled in this mode, further action is unnecessary. Test LPS before attempting to write IntMaskClear to disable interrupts. [Stefan R: whitespace changes] Signed-off-by: Peter Hurley Signed-off-by: Stefan Richter --- drivers/firewire/ohci.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) --- a/drivers/firewire/ohci.c +++ b/drivers/firewire/ohci.c @@ -3712,11 +3712,16 @@ static int pci_probe(struct pci_dev *dev static void pci_remove(struct pci_dev *dev) { - struct fw_ohci *ohci; + struct fw_ohci *ohci = pci_get_drvdata(dev); - ohci = pci_get_drvdata(dev); - reg_write(ohci, OHCI1394_IntMaskClear, ~0); - flush_writes(ohci); + /* + * If the removal is happening from the suspend state, LPS won't be + * enabled and host registers (eg., IntMaskClear) won't be accessible. + */ + if (reg_read(ohci, OHCI1394_HCControlSet) & OHCI1394_HCControl_LPS) { + reg_write(ohci, OHCI1394_IntMaskClear, ~0); + flush_writes(ohci); + } cancel_work_sync(&ohci->bus_reset_work); fw_core_remove_card(&ohci->card);