The EliteDesk 800 G6 stores a raw WMI string within the ACPI object in its BIOS corresponding to one instance of HPBIOS_PlatformEvents.Name. This is evidently a valid way of representing a WMI data item as far as the Microsoft ACPI-WMI mapper is concerned, but is preventing the driver from loading. As this seems quite rare, add a machine-limited workaround for now. Reported-by: Lukasz Stelmach <l.stelmach@xxxxxxxxxxx> Closes: https://lore.kernel.org/linux-hwmon/7850a0bd-60e7-88f8-1d6c-0bb0e3234fdc@xxxxxxxxxxxx/ Signed-off-by: James Seo <james@xxxxxxxxxx> --- Was converting to UTF-8 a good idea? There's also not much UTF-16 validation, because at the moment it's only being done on one machine with a known input. --- drivers/hwmon/hp-wmi-sensors.c | 57 ++++++++++++++++++++++++++++++++-- 1 file changed, 55 insertions(+), 2 deletions(-) diff --git a/drivers/hwmon/hp-wmi-sensors.c b/drivers/hwmon/hp-wmi-sensors.c index 17ae62f88bbf..c82a9bbf16ca 100644 --- a/drivers/hwmon/hp-wmi-sensors.c +++ b/drivers/hwmon/hp-wmi-sensors.c @@ -17,13 +17,17 @@ * Available: https://github.com/linuxhw/ACPI * [4] P. Rohár, "bmfdec - Decompile binary MOF file (BMF) from WMI buffer", * 2017. [Online]. Available: https://github.com/pali/bmfdec + * [5] Microsoft Corporation, "Driver-Defined WMI Data Items", 2017. [Online]. + * Available: https://learn.microsoft.com/en-us/windows-hardware/drivers/kernel/driver-defined-wmi-data-items */ #include <linux/acpi.h> #include <linux/debugfs.h> +#include <linux/dmi.h> #include <linux/hwmon.h> #include <linux/jiffies.h> #include <linux/mutex.h> +#include <linux/nls.h> #include <linux/units.h> #include <linux/wmi.h> @@ -52,6 +56,10 @@ #define HP_WMI_MAX_PROPERTIES 32U #define HP_WMI_MAX_INSTANCES 32U +/* DMI board names for machines requiring workarounds. */ + +#define HP_WMI_BOARD_NAME_ELITEDESK_800_G6 "870C" + enum hp_wmi_type { HP_WMI_TYPE_OTHER = 1, HP_WMI_TYPE_TEMPERATURE = 2, @@ -412,6 +420,30 @@ static char *hp_wmi_strdup(struct device *dev, const char *src) return dst; } +/* hp_wmi_wstrdup - hp_wmi_strdup, but for a raw WMI string */ +static char *hp_wmi_wstrdup(struct device *dev, const u8 *buf) +{ + const wchar_t *src; + size_t len; + char *dst; + int i; + + /* WMI strings are length-prefixed UTF-16. See [5]. */ + src = (wchar_t *)buf; + len = min(*src++ / sizeof(*src), (size_t)HP_WMI_MAX_STR_SIZE - 1); + while (len && !src[len - 1]) + len--; + + dst = devm_kmalloc(dev, (len + 1) * sizeof(*dst), GFP_KERNEL); + if (!dst) + return NULL; + + i = utf16s_to_utf8s(src, len, UTF16_LITTLE_ENDIAN, dst, len); + dst[i] = '\0'; + + return strim(dst); +} + /* * hp_wmi_get_wobj - poll WMI for a WMI object instance * @guid: WMI object GUID @@ -442,6 +474,21 @@ static u8 hp_wmi_wobj_instance_count(const char *guid) return clamp(count, 0, (int)HP_WMI_MAX_INSTANCES); } +static bool is_raw_wmi_string(const acpi_object_type property_map[], int prop) +{ + const char *board_name; + + if (property_map != hp_wmi_platform_events_property_map || + prop != HP_WMI_PLATFORM_EVENTS_PROPERTY_NAME) + return false; + + board_name = dmi_get_system_info(DMI_BOARD_NAME); + if (!board_name) + return false; + + return !strcmp(board_name, HP_WMI_BOARD_NAME_ELITEDESK_800_G6); +} + static int check_wobj(const union acpi_object *wobj, const acpi_object_type property_map[], int last_prop) { @@ -462,8 +509,12 @@ static int check_wobj(const union acpi_object *wobj, for (prop = 0; prop <= last_prop; prop++) { type = elements[prop].type; valid_type = property_map[prop]; - if (type != valid_type) + if (type != valid_type) { + if (type == ACPI_TYPE_BUFFER && + is_raw_wmi_string(property_map, prop)) + continue; return -EINVAL; + } } return 0; @@ -480,7 +531,9 @@ static int extract_acpi_value(struct device *dev, break; case ACPI_TYPE_STRING: - *out_string = hp_wmi_strdup(dev, strim(element->string.pointer)); + *out_string = element->type == ACPI_TYPE_BUFFER ? + hp_wmi_wstrdup(dev, element->buffer.pointer) : + hp_wmi_strdup(dev, strim(element->string.pointer)); if (!*out_string) return -ENOMEM; break; base-commit: 0f564130e5c76f1e5cf0008924f6a6cd138929d9 -- 2.39.2
