From: Rafael J. Wysocki <rjw@xxxxxxx> It turns out that there are devices whose power states cannot be set by ACPI (the _PRn and _PSn methods are not available for them), but it still is necessary to use ACPI for setting up those devices to wake up the system from sleep states. Then, according to the ACPI specification (ACPI 5.0 and earlier), if there are _SxD and/or _SxW methods defined for those devices, the results returned by them should be taken into consideration. Moreover, some hardware vendors seem to use this requirement to work around hardware and/or firmware bugs, so it's better to follow it (which we don't do at the moment) to avoid some nasty suspend/resume issues that are quite difficult to debug. This change is based on a patch from Oleksij Rempel. References: https://bugzilla.kernel.org/show_bug.cgi?id=42728 Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx> --- drivers/pci/pci.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) Index: linux/drivers/pci/pci.c =================================================================== --- linux.orig/drivers/pci/pci.c +++ linux/drivers/pci/pci.c @@ -1691,10 +1691,16 @@ pci_power_t pci_target_state(struct pci_ { pci_power_t target_state = PCI_D3hot; - if (platform_pci_power_manageable(dev)) { + /* + * It turns out that there are devices whose power states cannot be set + * by the platform, although their wakeup capabilities depend on it. + * The platform should be called to choose the target low-power states + * of those devices too. + */ + if (platform_pci_power_manageable(dev) + || (device_may_wakeup(&dev->dev) && platform_pci_can_wakeup(dev))) { /* - * Call the platform to choose the target state of the device - * and enable wake-up from this state if supported. + * Call the platform to choose the target state of the device. */ pci_power_t state = platform_pci_choose_state(dev); _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/linux-pm
