FAILED: patch "[PATCH] PCI/sysfs: Ensure devices are powered for config reads" failed to apply to 5.4-stable tree
Subsystems (2)
[email protected]
maintainerThe patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 48991e4935078b05f80616c75d1ee2ea3ae18e58
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025101641-squire-emboss-834e@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 48991e4935078b05f80616c75d1ee2ea3ae18e58 Mon Sep 17 00:00:00 2001
From: Brian Norris <[email protected]>
Date: Wed, 24 Sep 2025 09:57:11 -0700
Subject: [PATCH] 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").
drivers/pci/pci-sysfs.c +19 -1
@@ -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 ;