Messages in this thread Patch in this message | | | From | Kai-Heng Feng <> | Subject | [PATCH v4] platform/x86: dell-laptop: Fix bogus keyboard backlight sysfs interface | Date | Tue, 20 Jun 2017 11:05:19 +0800 |
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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> ---
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; } -- 2.13.1
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