On Thursday 11 June 2009, Jesse Barnes wrote: > On Tue, 26 May 2009 21:52:29 +0200 > "Rafael J. Wysocki" <rjw@xxxxxxx> wrote: > > > On Monday 18 May 2009, Rafael J. Wysocki wrote: > > > From: Rafael J. Wysocki <rjw@xxxxxxx> > > > > > > After attempting to change the power state of a PCI device > > > pci_raw_set_power_state() doesn't check if the value it wrote into > > > the device's PCI_PM_CTRL register has been stored in there. Still, > > > it modifies the device's current_state field as though that's the > > > case. This may cause the driver of the device to think that its > > > power state has been changed while in fact it hasn't. > > > > > > To prevent such situations from happening modify > > > pci_raw_set_power_state() so that it reads the device's PCI_PM_CTRL > > > register after writing into it and uses the value read from the > > > register to update the device's current_state field. Also make it > > > return -EIO if the new state of the device is not equal to the state > > > requested by the called. > > > > > > To distinguish this error condition from the other ones make > > > pci_raw_set_power_state() return -ENOSYS instead of -EIO when it is > > > impossible to change the power state of the device, because it > > > doesn't support the native PCI PM at all or the requested target > > > state is not supported by it. > > > > Having reconsidered it I think that -ENODEV is probably better than > > -ENOSYS for this purpose. Updated patch follows. > > Applied to linux-next, thanks Rafael. Please drop. It has been reported by Jiri to cause a regression to happen. Best, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
