summaryrefslogtreecommitdiff
path: root/drivers/pci/pci.c
diff options
context:
space:
mode:
authorBjorn Helgaas <bhelgaas@google.com>2019-08-01 11:50:56 -0500
committerBjorn Helgaas <bhelgaas@google.com>2019-11-20 17:36:48 -0600
commit327ccbbcc1497bff6d6f543c1f37c43a1653671f (patch)
treea1f1939be228f9bd952bc6a9d4bc9784e8ea4148 /drivers/pci/pci.c
parente43f15ea2f6d6858675fa1baa5cb624f17269af0 (diff)
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.c6
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.