[ltp] tpacpi bug in tpacpi::thinklight/brightness for X1 Carbon

Chris Schumann linux-thinkpad@linux-thinkpad.org
Mon, 30 Dec 2013 08:48:01 -0600

I also have an X1 Carbon (with touchscreen!) model 3443-CTO.

I'm happy to help and will send you the output from my system too.


On 12/29/2013 08:15 PM, Henrique de Moraes Holschuh wrote:
> On Sun, 29 Dec 2013, Sandro wrote:
>> The Lenovo X1 Carbon is gaining populairty as it's easily one of the
>> prettiest alternatives to the McBook Air.
>> For a while, I thought the keyboard backlight couldn't be controlled
>> through tpacpi, period. After asking a question <
>> http://askubuntu.com/questions/383501/> I got an interesting answer:
>> The keyboard backlight can in fact be turned off using the following
>> command:
>> echo 0 > /sys/class/leds/tpacpi\:\:thinklight/brightness
>> It's just that it cannot be turned /on/, which is what I am trying to do.
>> I can't be certain, but if the current tpacpi can turn the light off, it
>> gives me the impression that turning it on is just a bugfix away.
>> I cannot find an issuetracker for Github or Sourceforce, so I thought maybe
>> one of the devs (is that still Henrique de Moraes Holschuh AKA Hmh?) will
>> read this.
> I am reading this, but I can't do much without access to a X1.  The
> thinklight control uses a specific ACPI method, so your X1 has it or it
> would not have turned anything off.
> It likely wants a different parameter to enable the keyboard backlight
> (which stands to reason, since it is not a thinklight).  Since the turn-off
> command worked, if we're lucky it is a bitfield and it can be used to
> separately control the thinklight and the keyboard backlight.
> I won't promise anything, but send me the ACPI dump of your X1 (update it to
> the latest BIOS/EFI first).  Use a recent version of the ACPI tools,
> preferably "acpidump" from the latest Linux kernel tree (it is inside the
> tools/power/acpi directory of the kernel source.  Type Make there to build).
> Your linux distro might have it packaged.
> I also need the output of dmidecode.  Remove all serial numbers and UUIDs
> before you send it to me (replace their digits with "X").