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| author | Brian Norris <briannorris@google.com> | 2025-09-24 09:57:11 -0700 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2025-09-24 14:02:39 -0500 |
| commit | 48991e4935078b05f80616c75d1ee2ea3ae18e58 (patch) | |
| tree | 98e1deac5e1142e9e41b485f9c928c159c7ef4b2 /drivers/pci/pci-sysfs.c | |
| parent | PCI/PM: Skip resuming to D0 if device is disconnected (diff) | |
| download | linux-48991e4935078b05f80616c75d1ee2ea3ae18e58.tar.gz linux-48991e4935078b05f80616c75d1ee2ea3ae18e58.zip | |
PCI/sysfs: Ensure devices are powered for config reads
The "max_link_width", "current_link_speed", "current_link_width",
"secondary_bus_number", and "subordinate_bus_number" sysfs files all access
config registers, but they don't check the runtime PM state. If the device
is in D3cold or a parent bridge is suspended, we may see -EINVAL, bogus
values, or worse, depending on implementation details.
Wrap these access in pci_config_pm_runtime_{get,put}() like most of the
rest of the similar sysfs attributes.
Notably, "max_link_speed" does not access config registers; it returns a
cached value since d2bd39c0456b ("PCI: Store all PCIe Supported Link
Speeds").
Fixes: 56c1af4606f0 ("PCI: Add sysfs max_link_speed/width, current_link_speed/width, etc")
Signed-off-by: Brian Norris <briannorris@google.com>
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20250924095711.v2.1.Ibb5b6ca1e2c059e04ec53140cd98a44f2684c668@changeid
Diffstat (limited to 'drivers/pci/pci-sysfs.c')
| -rw-r--r-- | drivers/pci/pci-sysfs.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 5eea14c1f7f5..2b231ef1dac9 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -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; |