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Merge branch 'pci/pm'

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- If a device has already been disconnected, e.g., by a hotplug removal,
  don't bother trying to resume it to D0 when detaching the driver (Mario
  Limonciello)

- Ensure devices are powered up before config reads for 'max_link_width',
  'current_link_speed', 'current_link_width', 'secondary_bus_number', and
  'subordinate_bus_number' sysfs files (Brian Norris)

* pci/pm:
  PCI/sysfs: Ensure devices are powered for config reads
  PCI/PM: Skip resuming to D0 if device is disconnected
This commit is contained in:
Bjorn Helgaas
2025-10-03 12:13:11 -05:00
parent 0bb65e3249 48991e4935
commit 4c5cd8d641
2 changed files with 24 additions and 1 deletions
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20
drivers/pci/pci-sysfs.c
View File

@@ -201,8 +201,14 @@ static ssize_t max_link_width_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct pci_dev *pdev = to_pci_dev(dev);
ssize_t ret;
return sysfs_emit(buf, "%u\n", pcie_get_width_cap(pdev));
/* We read PCI_EXP_LNKCAP, so we need the device to be accessible. */
pci_config_pm_runtime_get(pdev);
ret = sysfs_emit(buf, "%u\n", pcie_get_width_cap(pdev));
pci_config_pm_runtime_put(pdev);
return ret;
}
static DEVICE_ATTR_RO(max_link_width);
@@ -214,7 +220,10 @@ static ssize_t current_link_speed_show(struct device *dev,
int err;
enum pci_bus_speed speed;
pci_config_pm_runtime_get(pci_dev);
err = pcie_capability_read_word(pci_dev, PCI_EXP_LNKSTA, &linkstat);
pci_config_pm_runtime_put(pci_dev);
if (err)
return -EINVAL;
@@ -231,7 +240,10 @@ static ssize_t current_link_width_show(struct device *dev,
u16 linkstat;
int err;
pci_config_pm_runtime_get(pci_dev);
err = pcie_capability_read_word(pci_dev, PCI_EXP_LNKSTA, &linkstat);
pci_config_pm_runtime_put(pci_dev);
if (err)
return -EINVAL;
@@ -247,7 +259,10 @@ static ssize_t secondary_bus_number_show(struct device *dev,
u8 sec_bus;
int err;
pci_config_pm_runtime_get(pci_dev);
err = pci_read_config_byte(pci_dev, PCI_SECONDARY_BUS, &sec_bus);
pci_config_pm_runtime_put(pci_dev);
if (err)
return -EINVAL;
@@ -263,7 +278,10 @@ static ssize_t subordinate_bus_number_show(struct device *dev,
u8 sub_bus;
int err;
pci_config_pm_runtime_get(pci_dev);
err = pci_read_config_byte(pci_dev, PCI_SUBORDINATE_BUS, &sub_bus);
pci_config_pm_runtime_put(pci_dev);
if (err)
return -EINVAL;

5
drivers/pci/pci.c
View File

@@ -1374,6 +1374,11 @@ int pci_power_up(struct pci_dev *dev)
return -EIO;
}
if (pci_dev_is_disconnected(dev)) {
dev->current_state = PCI_D3cold;
return -EIO;
}
pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
if (PCI_POSSIBLE_ERROR(pmcsr)) {
pci_err(dev, "Unable to change power state from %s to D0, device inaccessible\n",