| Message ID | 20190822200551.129039-4-helgaas@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
| Series | PCI: Add PCI_ERROR_RESPONSE, check for errors | expand |
On Thu, Aug 22, 2019 at 10:06 PM Bjorn Helgaas <helgaas@kernel.org> wrote: > > From: Bjorn Helgaas <bhelgaas@google.com> > > pci_raw_set_power_state() uses the Power Management capability to change a > device's power state. The capability is in config space, which is > accessible in D0, D1, D2, and D3hot, but not in D3cold. > > If we call pci_raw_set_power_state() on a device that's in D3cold, config > reads fail and return ~0 data, which we erroneously interpreted as "the > device is in D3hot", leading to messages like this: > > pcieport 0000:03:00.0: Refused to change power state, currently in D3 > > The PCI_PM_CTRL has several RsvdP fields, so ~0 is never a valid register > value. Notice if we get that data, print a more informative message, and > return an error. > > Changing the power state of a device from D3cold must be done by a platform > power management method or some other non-config space mechanism. > > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > drivers/pci/pci.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 5f0a3145c3f2..41112af189a8 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -853,6 +853,12 @@ 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) PCI_ERROR_RESPONSE) { > + pci_err(dev, "can't access config space to change power state from %s to %s\n", > + pci_power_name(dev->current_state), > + pci_power_name(state)); > + return -EIO; > + } > > /* > * If we're (effectively) in D3, force entire word to 0. > @@ -893,8 +899,9 @@ static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state) > pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr); > dev->current_state = (pmcsr & PCI_PM_CTRL_STATE_MASK); > if (dev->current_state != state && printk_ratelimit()) > - pci_info(dev, "refused to change power state (currently %s)\n", > - pci_power_name(dev->current_state)); > + pci_info(dev, "refused to change power state from %s to %s\n", > + pci_power_name(dev->current_state), > + pci_power_name(state)); > > /* > * According to section 5.4.1 of the "PCI BUS POWER MANAGEMENT > -- > 2.23.0.187.g17f5b7556c-goog >
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 5f0a3145c3f2..41112af189a8 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -853,6 +853,12 @@ 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) PCI_ERROR_RESPONSE) { + pci_err(dev, "can't access config space to change power state from %s to %s\n", + pci_power_name(dev->current_state), + pci_power_name(state)); + return -EIO; + } /* * If we're (effectively) in D3, force entire word to 0. @@ -893,8 +899,9 @@ static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state) pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr); dev->current_state = (pmcsr & PCI_PM_CTRL_STATE_MASK); if (dev->current_state != state && printk_ratelimit()) - pci_info(dev, "refused to change power state (currently %s)\n", - pci_power_name(dev->current_state)); + pci_info(dev, "refused to change power state from %s to %s\n", + pci_power_name(dev->current_state), + pci_power_name(state)); /* * According to section 5.4.1 of the "PCI BUS POWER MANAGEMENT