On 8/21/2025 1:26 AM, Brian Norris wrote:
From: Brian Norris briannorris@google.com
max_link_speed, max_link_width, current_link_speed, current_link_width, secondary_bus_number, and subordinate_bus_number all access config registers, but they don't check the runtime PM state. If the device is in D3cold, we may see -EINVAL or even bogus values.
My understanding, if your device is in D3cold, returning of -EINVAL is the right behavior. >
Wrap these access in pci_config_pm_runtime_{get,put}() like most of the rest of the similar sysfs attributes.
Fixes: 56c1af4606f0 ("PCI: Add sysfs max_link_speed/width, current_link_speed/width, etc") Cc: stable@vger.kernel.org Signed-off-by: Brian Norris briannorris@google.com Signed-off-by: Brian Norris briannorris@chromium.org
drivers/pci/pci-sysfs.c | 32 +++++++++++++++++++++++++++++--- 1 file changed, 29 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 5eea14c1f7f5..160df897dc5e 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -191,9 +191,16 @@ static ssize_t max_link_speed_show(struct device *dev, struct device_attribute *attr, char *buf) { struct pci_dev *pdev = to_pci_dev(dev);
- ssize_t ret;
- pci_config_pm_runtime_get(pdev);
This function would potentially change the power state of device, that would be a complex process, beyond the meaning of max_link_speed_show(), given the semantics of these functions ( max_link_speed_show()/max_link_width_show()/current_link_speed_show()/ ....), this cannot be done !
Thanks, Ethan>
- return sysfs_emit(buf, "%s\n",
pci_speed_string(pcie_get_speed_cap(pdev)));
- ret = sysfs_emit(buf, "%s\n",
pci_speed_string(pcie_get_speed_cap(pdev)));- pci_config_pm_runtime_put(pdev);
- return ret; } static DEVICE_ATTR_RO(max_link_speed);
@@ -201,8 +208,15 @@ 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;
- pci_config_pm_runtime_get(pdev);
- ret = sysfs_emit(buf, "%u\n", pcie_get_width_cap(pdev));
- return 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 +228,10 @@ 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 +248,10 @@ 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 +267,10 @@ 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 +286,10 @@ 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;