On Thu, 11 Jun 2009 12:53:16 -0700 "Rafael J. Wysocki" <rjw@xxxxxxx> wrote: > 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. Ah as I went through the rebase I thought I remembered something like that. Will drop. Thanks, -- Jesse Barnes, Intel Open Source Technology Center -- 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
