All recent ThinkPad BIOS-es support the GSKL method used to query the
keyboard-layout used by the ECFW for the SHIFT + other-key key-press
emulation for special keys such as e.g. the '=', '(' and ')' keys
above the numpad on 15" models.
So just checking for the method is not a good indicator of the
model supporting getting/setting the keyboard_lang.
On models where this is not supported GSKL succeeds, but it returns
METHOD_ERR in the returned integer to indicate that this is not
supported on this model.
Add a check for METHOD_ERR and return -ENODEV if it is set to
avoid registering a non-working keyboard_lang sysfs-attr on models
where this is not supported.
Cc: Nitin Joshi <njoshi1@xxxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
drivers/platform/x86/thinkpad_acpi.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index df2506974106..0b268e17cb7b 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -10356,6 +10356,13 @@ static int get_keyboard_lang(int *output)
if (!acpi_evalf(gskl_handle, &kbd_lang, NULL, "dd", 0x02000000))
return -EIO;
+ /*
+ * METHOD_ERR gets returned on devices where there are no special (e.g. '=',
+ * '(' and ')') keys which use layout dependent key-press emulation.
+ */
+ if (kbd_lang & METHOD_ERR)
+ return -ENODEV;
+
*output = kbd_lang;
return 0;
--
2.29.2
