@@ -10,12 +10,14 @@
#include <linux/acpi.h>
#include <linux/debugfs.h>
#include <linux/device.h>
+#include <linux/dev_printk.h>
#include <linux/kernel.h>
#include <linux/kstrtox.h>
#include <linux/math.h>
#include <linux/module.h>
#include <linux/limits.h>
#include <linux/power_supply.h>
+#include <linux/printk.h>
#include <linux/seq_file.h>
#include <linux/sysfs.h>
#include <linux/wmi.h>
@@ -27,6 +29,9 @@
#define DELL_DDV_SUPPORTED_INTERFACE 2
#define DELL_DDV_GUID "8A42EA14-4F2A-FD45-6422-0087F7A7E608"
+#define DELL_EPPID_LENGTH 20
+#define DELL_EPPID_EXT_LENGTH 23
+
enum dell_ddv_method {
DELL_DDV_BATTERY_DESIGN_CAPACITY = 0x01,
DELL_DDV_BATTERY_FULL_CHARGE_CAPACITY = 0x02,
@@ -196,6 +201,10 @@ static ssize_t eppid_show(struct device *dev, struct device_attribute *attr, cha
if (ret < 0)
return ret;
+ if (obj->string.length != DELL_EPPID_LENGTH && obj->string.length != DELL_EPPID_EXT_LENGTH)
+ dev_info_once(&data->wdev->dev, FW_INFO "Suspicious ePPID length (%d)\n",
+ obj->string.length);
+
ret = sysfs_emit(buf, "%s\n", obj->string.pointer);
kfree(obj);
On some systems (like the Dell Inspiron 3505), the acpi operation region holding the ePPID string is two bytes too short, causing acpi functions like ToString() to omit the last two bytes. This does not happen on Windows, supposedly due to their implementation of ToString() ignoring buffer boundaries. Inform users if the ePPID length differs from the Dell specification so they can complain to Dell to fix their BIOS. Tested on a Dell Inspiron 3505. Signed-off-by: Armin Wolf <W_Armin@gmx.de> --- drivers/platform/x86/dell/dell-wmi-ddv.c | 9 +++++++++ 1 file changed, 9 insertions(+) -- 2.30.2