From: Rafael J. Wysocki Date: Sun, 17 May 2009 18:17:06 +0000 (+0200) Subject: PCI PM: Fix initialization and kexec breakage for some devices X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=b3bad72e494fb2ff0c81be4ca2ddb94adf6a47c2;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git PCI PM: Fix initialization and kexec breakage for some devices Recent PCI PM changes introduced a bug that causes some devices to be mishandled after kexec and during early initialization. The failure scenario in the kexec case is the following: * Assume a PCI device is not power-manageable by the platform and has PCI_PM_CTRL_NO_SOFT_RESET set in PMCSR. * The device is put into D3 before kexec (using the native PCI PM). * After kexec, pci_setup_device() sets the device's power state to PCI_UNKNOWN. * pci_set_power_state(dev, PCI_D0) is called by the device's driver. * __pci_start_power_transition(dev, PCI_D0) is called and since the device is not power-manageable by the platform, it causes pci_update_current_state(dev, PCI_D0) to be called. As a result the device's current_state field is updated to PCI_D3, in accordance with the contents of its PCI PM registers. * pci_raw_set_power_state() is called and it changes the device power state to D0. *However*, it should also call pci_restore_bars() to reinitialize the device, but it doesn't, because the device's current_state field has been modified earlier. To prevent this from happening, modify pci_platform_power_transition() so that it doesn't use pci_update_current_state() to update the current_state field for devices that aren't power-manageable by the platform. Instead, this field should be updated directly for devices that don't support the native PCI PM. Signed-off-by: Rafael J. Wysocki Signed-off-by: Jesse Barnes --- diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 34bf0fdf5047..1a91bf9687af 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -557,7 +557,8 @@ static int pci_platform_power_transition(struct pci_dev *dev, pci_power_t state) } else { error = -ENODEV; /* Fall back to PCI_D0 if native PM is not supported */ - pci_update_current_state(dev, PCI_D0); + if (!dev->pm_cap) + dev->current_state = PCI_D0; } return error;