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| author |   Bjorn Helgaas <bhelgaas@google.com> | 2019-08-01 11:50:56 -0500 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2019-11-20 17:36:48 -0600 |
| commit | 327ccbbcc1497bff6d6f543c1f37c43a1653671f (patch) | |
| tree | a1f1939be228f9bd952bc6a9d4bc9784e8ea4148 /drivers/pci/pci.c | |
| parent | PCI/PM: Decode D3cold power state correctly (diff) | |
| download | wireguard-linux-327ccbbcc1497bff6d6f543c1f37c43a1653671f.tar.xz wireguard-linux-327ccbbcc1497bff6d6f543c1f37c43a1653671f.zip | |
PCI/PM: Return error when changing power state from D3cold
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. If we get that value, 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.
Link: https://lore.kernel.org/r/20190822200551.129039-4-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Diffstat (limited to 'drivers/pci/pci.c')
| -rw-r--r-- | drivers/pci/pci.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 3376c663035d..d6ff1a98bd8d 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) ~0) { + pci_err(dev, "can't change power state from %s to %s (config space inaccessible)\n", + pci_power_name(dev->current_state), + pci_power_name(state)); + return -EIO; + } /* * If we're (effectively) in D3, force entire word to 0. |