On Thu, Aug 01, 2019 at 12:26:51AM +0200, Rafael J. Wysocki wrote: > On Wednesday, July 31, 2019 11:30:01 PM CEST Bjorn Helgaas wrote: > > [+cc Thunderbolt folks, see > > https://lore.kernel.org/r/578BD3F1-B185-471B-A3EB-FF71BA34B822@xxxxxxxxxxxxx > > for beginning of thread] > > > > On Thu, Aug 01, 2019 at 12:04:29AM +0800, Kai-Heng Feng wrote: > > > Hi, > > > > > > After commit "ACPI: PM: Allow transitions to D0 to occur in special cases”, > > > > This is f850a48a0799 ("ACPI: PM: Allow transitions to D0 to occur in > > special cases"). > > > > > Thunderbolt on XPS 9380 spews the following when it runtime resumes: > > > [ 36.136554] pci_raw_set_power_state: 25 callbacks suppressed > > > [ 36.136558] pcieport 0000:03:00.0: Refused to change power state, > > > currently in D3 > > > > We really should be smarter about what we print here, maybe something > > like the patch below? > > > > pci_raw_set_power_state() prints "Refused to change power state" if > > (in this case) the value of (PCI_PM_CTRL & PCI_PM_CTRL_STATE_MASK) is > > 0x3. Most likely we got 0xffff from PCI_PM_CTRL because the device is > > in D3cold. If the device is in D3cold, pci_raw_set_power_state() has > > no hope of doing anything because it only uses PCI PM config > > registers, and they're inaccessible in D3cold. > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > > index 29ed5ec1ac27..63ca963ebff9 100644 > > --- a/drivers/pci/pci.c > > +++ b/drivers/pci/pci.c > > @@ -851,6 +852,11 @@ static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state) > > return -EIO; > > > > pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr); > > + if (pmcsr == (u16) ~0) { > > Is the "device not accessible" the only case in which we can get all ones from this? > > If so, the change will be fine by me. There are several RsvdP bits in that register, so it's not possible to read all ones except in error cases. I'll finish up a patch for it. Bjorn
