[ltp] cannot access acpi interface

Paul Bolle linux-thinkpad@linux-thinkpad.org
Tue, 11 Feb 2014 09:39:21 +0100

On Tue, 2014-02-11 at 08:27 +0100, fa-ml wrote:
> Reading this I tried:
>     $ root@x60s:/proc/acpi/ibm# echo "15 on" > led
>     bash: echo: write error: Operation not permitted
> Has anyone of you encountered the same problem? Is there a workaround?

>From Documentation/laptops/thinkpad-acpi.txt:
    LED control

    procfs: /proc/acpi/ibm/led
    sysfs attributes: as per LED class, see below for names


    Because misuse of the LEDs could induce an unaware user to perform
    dangerous actions (like undocking or ejecting a bay device while the
    buses are still active), or mask an important alarm (such as a nearly
    empty battery, or a broken battery), access to most LEDs is

    Unrestricted access to all LEDs requires that thinkpad-acpi be
    compiled with the CONFIG_THINKPAD_ACPI_UNSAFE_LEDS option enabled.
    Distributions must never enable this option.  Individual users that 
    are aware of the consequences are welcome to enabling it.

Perhaps you are trying to access one of the unsafe leds.

Paul Bolle