RFC PCI PM: Make new suspend-resume callbacks carry out core operations

Quoted 11 lines · Rafael J. Wysocki

Hi Len,

The patch below adds the callbacks that save/restore the standard PCI config registers, change the power state of the device etc. to the new suspend-resume callbacks (which are not yet used by device drivers), so that the drivers don't have to worry about these operations.

The saving and restoring of the standard PCI config registers is done with interrupts off, the other things are done with interrupts enabled.

The patch should apply to the current linux-next tree.

Below is a new version of the patch.

Now, the standard config spaces of devices are restored with interrupts disabled, but only if the bridges the devices are behind are in D0. Otherwise, the operation is attempted again with interrupts enabled (presumably the bridge would be put into D0 before that happens).

Also, pci_disable_device() is not called during resume and pci_reenable_device() is used to enable the devices that were enabled during suspend. This allows us to automatically call pci_set_master() for devices that were bus masters before suspend. Additionally, the pci_reenable_device() may be overriden by the driver, by disabling the device during suspend.

Finally, bridges are handled a bit differently from the regular devices (they are not put into low power states during suspend and pci_enable_wake() is not called for them.

The patch should apply on top of linux-next with the patch fixing pci_update_current_state() I sent yesterday
(http://marc.info/?l=linux-kernel&m=123039199607159&w=4).