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. > > Presumably there's some platform PM method that is supposed to take > the device out of D3cold, and maybe we're missing that somehow? Yes, there is. > Based on an lspci I found at [1], I suspect 03:00.0 is a Thunderbolt > switch leading to [bus 04-6d]. From your log, it looks like these > devices don't work: > > 03:00.0 Thunderbolt Upstream Port > 04:00.0 Thunderbolt Downstream Port > 04:01.0 Thunderbolt Downstream Port (Slot 1) > 04:02.0 Thunderbolt Downstream Port > 04:04.0 Thunderbolt Downstream Port (Slot 4) > 05:00.0 Thunderbolt NHI > 39:00.0 XHCI USB > > If 03:00.0 is stuck in D3cold, that would explain why none of these > things work. > > [1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1826125 > > > 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. > + pci_err(dev, "device not responding; can't change to power state D%d\n", > + state); But I wouldn't break this line. > + return -EIO; > + } > > /* > * If we're (effectively) in D3, force entire word to 0. > Thanks!
