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platform/x86: dell-laptop: Fix bogus keyboard backlight sysfs interface 

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@canonical.com>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
This commit is contained in:
Kai Heng Feng 2017-06-20 11:05:19 +08:00 committed by Andy Shevchenko
parent 62fc743caf
commit 1b1ffc57a1
1 changed files with 5 additions and 1 deletions
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6
drivers/platform/x86/dell-laptop.c
View File

@ -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;
}