ACK: [SRU] [Xenial] [PATCH 0/1] Fix keyboard led sysfs cannot control its brightness

Colin Ian King colin.king at
Tue May 30 08:41:34 UTC 2017

On 25/05/17 04:29, Kai-Heng Feng wrote:
> BugLink:
> Impact:
> On some new dell laptops, the keyboard led backlight sysfs cannot control its brightness:
>  dell_laptop: Setting old previous keyboard state failed
>  leds dell::kbd_backlight: Setting an LED's brightness failed (-6)
> Fix:
> Commit 9216e0dcb5533a999d544d0af8661118e0588e1d can fix the issue:
>  This patch adds support for retrieving current timeout AC values and also
>  updating them. Current timeout value in sysfs is displayed based on current
>  AC status, like current display brightness value.
> The patch uses dell_smbios_find_token() which is a refactored version of
> find_token_location(). I use the latter one to avoid unnecessary patch series.
> Test:
> Keyboad backlight now can be correctly controlled by sysfs
> "dell:kbd_backlight/brightness" on Dell Precision 3520.
> Pali Rohár (1):
>   platform/x86: dell-laptop: Add keyboard backlight timeout AC settings
>  drivers/platform/x86/dell-laptop.c | 59 ++++++++++++++++++++++++++++++++++----
>  1 file changed, 53 insertions(+), 6 deletions(-)
I'd like the all SRU specific details (impact/fix/test and also very
importantly the regression risk added to the bug report to make SRU
review a little easier.

This fix is from upstream, is targeted to a limited set of devices and
has positive test results.

Acked-by: Colin Ian King <colin.king at>

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