On Tuesday 20 June 2017 11:05:19 Kai-Heng Feng wrote: > 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> > --- > > v4: > Change commit log - not all models have ON token. > > v3: > Change the logic, there should be at least two modes present to claim it > supports backlight. Suggested by Pali Rohár. > > v2: > The only token can be found is actually KBD_LED_ON_TOKEN, which is BIT(5), > instead of KBD_LED_OFF_TOKEN. Change commit log accordingly. > > Use token bit to make the intention more clear. > Also consider kbd_mode_levels_count and kbd_info.levels, suggested by > Pali Rohár. > > Use XOR to simplify the bitmask comparison, suggested by > Andy Shevchenko. > > 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 ec202094bd50..f42159fd2031 100644 > --- a/drivers/platform/x86/dell-laptop.c > +++ b/drivers/platform/x86/dell-laptop.c > @@ -1510,7 +1510,11 @@ 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; > } > -- Pali Rohár pali.rohar@xxxxxxxxx
