From 36f9bd09920ed71c1b79db397170412b2de22319 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= Date: Fri, 14 Aug 2026 07:05:19 +0000 Subject: [PATCH] PCI/sysfs: Stop reporting _DSM failures as -EPERM MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently, dsm_get_label() returns the literal -1 on every failure path. The sysfs read path passes that value to userspace as -EPERM. Reading the "label" or "acpi_index" attribute on a platform where the Device Name _DSM returns a malformed result then fails with: $ cat /sys/bus/pci/devices/0000:00:08.3/label cat: /sys/bus/pci/devices/0000:00:08.3/label: Operation not permitted Nothing in that path performs a permission check, and the read fails the same way for a privileged reader. The error code points at a cause that does not exist, and tools such as lspci report it on every invocation. Return -ENODEV when the device has no ACPI companion, and -EIO when the _DSM evaluation fails or returns an object that cannot be parsed. Other _DSM users in the tree report such failures the same way. The set of reads that succeed, and the bytes they return, stay the same. Only the error code of reads that already fail differs. Fixes: 6058989bad05 ("PCI: Export ACPI _DSM provided firmware instance number and string name to sysfs") Link: https://github.com/pciutils/pciutils/issues/175 Signed-off-by: Krzysztof Wilczyński Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20260814070522.2327975-2-kwilczynski@kernel.org --- drivers/pci/pci-label.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/pci/pci-label.c b/drivers/pci/pci-label.c index 0c6446519640..255e0ecffb09 100644 --- a/drivers/pci/pci-label.c +++ b/drivers/pci/pci-label.c @@ -160,12 +160,12 @@ static int dsm_get_label(struct device *dev, char *buf, int len = 0; if (!handle) - return -1; + return -ENODEV; obj = acpi_evaluate_dsm(handle, &pci_acpi_dsm_guid, 0x2, DSM_PCI_DEVICE_NAME, NULL); if (!obj) - return -1; + return -EIO; tmp = obj->package.elements; if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 2 && @@ -190,7 +190,7 @@ static int dsm_get_label(struct device *dev, char *buf, ACPI_FREE(obj); - return len > 0 ? len : -1; + return len > 0 ? len : -EIO; } static ssize_t label_show(struct device *dev, struct device_attribute *attr,