From: Armin Wolf Date: Tue, 10 Jun 2025 05:55:26 +0000 (+0200) Subject: platform/x86: wmi: Fix WMI device naming issue X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=73f0f2b52c5ea67b3140b23f58d8079d158839c8;p=thirdparty%2Fkernel%2Fstable.git platform/x86: wmi: Fix WMI device naming issue When multiple WMI devices with the same GUID are present inside a given system, the WMI driver core might fail to register all of them. Consider the following scenario: WMI devices ([-]): 05901221-D566-11D1-B2F0-00A0C9062910 (on PNP0C14:00) 05901221-D566-11D1-B2F0-00A0C9062910-1 (on PNP0C14:01) If the WMI core driver somehow unbinds from PNP0C14:00, the following will happen upon rebinding: 1. The WMI driver core counts all registered WMI devices with a GUID of 05901221-D566-11D1-B2F0-00A0C9062910 (count: 1). 2. The new WMI device will be named "05901221-D566-11D1-B2F0-00A0C9062910-1" because another device with the same GUID is already registered (on PNP0C14:01). 3. The new WMI device cannot be registered due to a name conflict. Use a IDA when building the WMI device name to avoid such name collisions by ensuring that a given WMI device ID is not reused. Userspace applications using udev for WMI device detection are not impacted by this change. Additionally userspace applications that do fully support the existing naming scheme are also not impacted. Only userspace applications using hardcoded sysfs paths will break. Introduce a kconfig option for restoring the old naming scheme to give developers time to fix any compatibility issues. Tested on a Asus Prime B650-Plus. Signed-off-by: Armin Wolf Link: https://lore.kernel.org/r/20250610055526.23688-2-W_Armin@gmx.de Reviewed-by: Ilpo Järvinen Signed-off-by: Ilpo Järvinen --- diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig index 43055df448274..49ca98df47fd8 100644 --- a/drivers/platform/x86/Kconfig +++ b/drivers/platform/x86/Kconfig @@ -37,6 +37,15 @@ config ACPI_WMI It is safe to enable this driver even if your DSDT doesn't define any ACPI-WMI devices. +config ACPI_WMI_LEGACY_DEVICE_NAMES + bool "Use legacy WMI device naming scheme" + depends on ACPI_WMI + help + Say Y here to force the WMI driver core to use the old WMI device naming + scheme when creating WMI devices. Doing so might be necessary for some + userspace applications but will cause the registration of WMI devices with + the same GUID to fail in some corner cases. + config WMI_BMOF tristate "WMI embedded Binary MOF driver" depends on ACPI_WMI diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c index e46453750d5f1..21b7e54bd7ab3 100644 --- a/drivers/platform/x86/wmi.c +++ b/drivers/platform/x86/wmi.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -74,6 +75,8 @@ struct wmi_guid_count_context { int count; }; +static DEFINE_IDA(wmi_ida); + /* * If the GUID data block is marked as expensive, we must enable and * explicitily disable data collection. @@ -978,6 +981,19 @@ static int guid_count(const guid_t *guid) return context.count; } +static int wmi_dev_set_name(struct wmi_block *wblock, int count) +{ + if (IS_ENABLED(CONFIG_ACPI_WMI_LEGACY_DEVICE_NAMES)) { + if (count) + return dev_set_name(&wblock->dev.dev, "%pUL-%d", &wblock->gblock.guid, + count); + else + return dev_set_name(&wblock->dev.dev, "%pUL", &wblock->gblock.guid); + } + + return dev_set_name(&wblock->dev.dev, "%pUL-%d", &wblock->gblock.guid, wblock->dev.dev.id); +} + static int wmi_create_device(struct device *wmi_bus_dev, struct wmi_block *wblock, struct acpi_device *device) @@ -986,7 +1002,7 @@ static int wmi_create_device(struct device *wmi_bus_dev, struct acpi_device_info *info; acpi_handle method_handle; acpi_status status; - int count; + int count, ret; if (wblock->gblock.flags & ACPI_WMI_EVENT) { wblock->dev.dev.type = &wmi_type_event; @@ -1057,11 +1073,18 @@ static int wmi_create_device(struct device *wmi_bus_dev, if (count < 0) return count; - if (count) { - dev_set_name(&wblock->dev.dev, "%pUL-%d", &wblock->gblock.guid, count); + if (count) set_bit(WMI_GUID_DUPLICATED, &wblock->flags); - } else { - dev_set_name(&wblock->dev.dev, "%pUL", &wblock->gblock.guid); + + ret = ida_alloc(&wmi_ida, GFP_KERNEL); + if (ret < 0) + return ret; + + wblock->dev.dev.id = ret; + ret = wmi_dev_set_name(wblock, count); + if (ret < 0) { + ida_free(&wmi_ida, wblock->dev.dev.id); + return ret; } device_initialize(&wblock->dev.dev); @@ -1147,6 +1170,7 @@ static int parse_wdg(struct device *wmi_bus_dev, struct platform_device *pdev) dev_err(wmi_bus_dev, "failed to register %pUL\n", &wblock->gblock.guid); + ida_free(&wmi_ida, wblock->dev.dev.id); put_device(&wblock->dev.dev); } } @@ -1246,7 +1270,10 @@ static void acpi_wmi_notify_handler(acpi_handle handle, u32 event, void *context static int wmi_remove_device(struct device *dev, void *data) { + int id = dev->id; + device_unregister(dev); + ida_free(&wmi_ida, id); return 0; }