On Tue, Oct 25, 2022 at 04:25:21PM -0500, Bjorn Helgaas wrote: > N.B. This changes the order of pmac_ohci_off() and pmac_ohci_on(). > Previously, pmac_ohci_off() was called *after* pci_save_state() and > pci_set_power_state(), and this change calls it *before*. > > Similarly, pmac_ohci_on() was previously called *before* > pci_set_power_state() and pci_restore_state() and this change calls it > *after*. Seems likely the ordering change may break things. pmac_ohci_on/off() toggles PMAC_FTR_1394_ENABLE, which is defined as: * enable/disable the firewire cell of an uninorth ASIC. It sounds like it will cut power to the firewire controller and I'd expect that pci_save_state() will then not be able to access config space. The only way to make this work is to define a struct dev_pm_domain whose ->suspend_noirq callback first invokes the pci_bus_type ->suspend_noirq callback and then cuts power to the firewire cell by calling pmac_ohci_off(). I've done something like this for Thunderbolt power management on x86 Macs a few years back but didn't get around to upstream it so far: https://github.com/l1k/linux/commit/4db7f0b1f5c9 Thanks, Lukas
