diff options
| author | Feiyang Chen <chenfeiyang@loongson.cn> | 2023-08-24 09:37:38 +0800 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2023-08-25 16:17:11 -0500 |
| commit | 5694ba13b004eea683c6d4faeb6d6e7a9636bda0 (patch) | |
| tree | 974e42d48d40a7204b8d89467077d3d7ad408d87 /drivers/pci/pci.c | |
| parent | 06c2afb862f9da8dc5efa4b6076a0e48c3fbaaa5 (diff) | |
PCI/PM: Only read PCI_PM_CTRL register when available
For a device with no Power Management Capability, pci_power_up() previously
returned 0 (success) if the platform was able to put the device in D0,
which led to pci_set_full_power_state() trying to read PCI_PM_CTRL, even
though it doesn't exist.
Since dev->pm_cap == 0 in this case, pci_set_full_power_state() actually
read the wrong register, interpreted it as PCI_PM_CTRL, and corrupted
dev->current_state. This led to messages like this in some cases:
pci 0000:01:00.0: Refused to change power state from D3hot to D0
To prevent this, make pci_power_up() always return a negative failure code
if the device lacks a Power Management Capability, even if non-PCI platform
power management has been able to put the device in D0. The failure will
prevent pci_set_full_power_state() from trying to access PCI_PM_CTRL.
Fixes: e200904b275c ("PCI/PM: Split pci_power_up()")
Link: https://lore.kernel.org/r/20230824013738.1894965-1-chenfeiyang@loongson.cn
Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: stable@vger.kernel.org # v5.19+
Diffstat (limited to 'drivers/pci/pci.c')
| -rw-r--r-- | drivers/pci/pci.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 60230da957e0..39728196e295 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1226,6 +1226,10 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout) * * On success, return 0 or 1, depending on whether or not it is necessary to * restore the device's BARs subsequently (1 is returned in that case). + * + * On failure, return a negative error code. Always return failure if @dev + * lacks a Power Management Capability, even if the platform was able to + * put the device in D0 via non-PCI means. */ int pci_power_up(struct pci_dev *dev) { @@ -1242,9 +1246,6 @@ int pci_power_up(struct pci_dev *dev) else dev->current_state = state; - if (state == PCI_D0) - return 0; - return -EIO; } @@ -1302,8 +1303,12 @@ static int pci_set_full_power_state(struct pci_dev *dev) int ret; ret = pci_power_up(dev); - if (ret < 0) + if (ret < 0) { + if (dev->current_state == PCI_D0) + return 0; + return ret; + } pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr); dev->current_state = pmcsr & PCI_PM_CTRL_STATE_MASK; |