On Saturday, 6 of December 2008, Linus Torvalds wrote: > > On Sat, 6 Dec 2008, Rafael J. Wysocki wrote: > > > > Rework the handling of suspend and resume of PCI devices which have > > no drivers or the drivers of which do not provide any suspend-resume > > callbacks in such a way that their standard PCI configuration > > registers will be saved and restored with interrupts disabled. > > Ok, I think this is good, but I _also_ think that we should do one more > fix: > > - if a device uses the new-format suspend/resume structure, we should do > the low-level save-restore _unconditionally_ in the PCI layer. > > Because apparently there is only a single user of the new format, and that > single user got it wrong. So wouldn't it be much nicer to just _remove_ > the code from the USB host controllers that does the save/restore thing. USB doesn't use that for PCI suspend-resume, it uses it for suspend-resume of USB devices behind the controller. > Quite frankly, the USB code really does look wrong. Not just in that it > enables the BAR's before restoring them, but on the suspend side it > actually puts the device into D3_hot _before_ it then does the whole > "pci_enable_wake()", which I'm not at all sure will necessarily work. I'm > pretty sure that you should enable wakeup events _before_ going to sleep. Yeah. Or simply use pci_prepare_to_sleep() and be done with it. > If the generic PCI layer unconditionally did the suspend as the last thing > it does (and the resume as the first thing), then drivers couldn't do > insane things like that, even by mistake. > > Hmm? OK But then we will save the device's registers in the "sleeping" state. Is this going to be entirely correct in all possible cases? [pci_save_state() doesn't save the PM registers, so that _should_ be correct, but I don't have _that_ much experience with these things.] Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
