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

Chris Schumann linux-thinkpad@linux-thinkpad.org
Wed, 01 Jan 2014 08:24:32 -0600

On 12/31/2013 07:42 AM, Henrique de Moraes Holschuh wrote:
> On Tue, 31 Dec 2013, Henrique de Moraes Holschuh wrote:
>> On Mon, 30 Dec 2013, Chris Schumann wrote:
>>>> 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.
>> Meh.  The "off" command uses the generic "update-cmos" handler (UCMS), which
>> often just stores info in come nvram instead of doing something.  In the
>> keyboard backlight case, the OFF command for the lights (thinklight and
>> apparently backlight) actually turns them off, but if there is an ON
>> command, it is command 0x0e (which is supposed to just toggle the
>> thinklight).
>> Please test it, see if thinkpad-acpi will give you the /proc/acpi/ibm/cmos
>> file.  If it still does in your kernel, echo "0x0e" > /proc/acpi/ibm/cmos
>> might be useful.  Other interesting cmos commands might be 0x0b to 0x0d.
> It is also available in sysfs (far more likely to be supported than the
> /proc node in a recent kernel).  It is likely at
> /sys/bus/platform/drivers/thinkpad_acpi/cmos_command.
That directory doesn't exist for me, but I have 
/sys/bus/platform/drivers/thinkpad_acpi/thinkpad_acpi/ and a whole bunch 
of stuff under that.