From: Kai Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> [ Upstream commit 1b1ffc57a1b2edf58e803e463980b326765a237f ] Dell Latitude 3160 does not have keyboard backlight, but there is a sysfs interface for it, which does nothing at all. KBD_LED_ON_TOKEN is the only token can be found. Since it doesn't have KBD_LED_OFF_TOKEN or KBD_LED_AUTO_*_TOKEN, it should be safe to assume at least two tokens should be present to support keyboard backlight. Not all models have ON token - they may have multiple AUTO tokens instead. Models which do not use SMBIOS token to control keyboard backlight, also have this issue. Brightness level is 0 on these models. Verified on Dell Inspiron 3565. Reports keyboard backlight is supported only when at least two modes are present. Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> Reviewed-by: Pali Rohár <pali.rohar@xxxxxxxxx> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> --- drivers/platform/x86/dell-laptop.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c index aaeeae81e3a9..c6e5ca2b8ae9 100644 --- a/drivers/platform/x86/dell-laptop.c +++ b/drivers/platform/x86/dell-laptop.c @@ -1608,7 +1608,11 @@ static void kbd_init(void) ret = kbd_init_info(); kbd_init_tokens(); - if (kbd_token_bits != 0 || ret == 0) + /* + * Only supports keyboard backlight when it has at least two modes. + */ + if ((ret == 0 && (kbd_info.levels != 0 || kbd_mode_levels_count >= 2)) + || kbd_get_valid_token_counts() >= 2) kbd_led_present = true; } -- 2.15.1