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    ACPI: Make Embedded Controller command timeout delay configurable · 7a18e96d
    Thomas Renninger 提交于
    Here and then there show up machines which need higher timeout values.
    Finding this on affected machines can be cumbersome, because
    ACPI_EC_DELAY is a compile option -> make it configurable via boot param.
    
    This can even be provided writable at runtime via:
    /sys/modules/acpi/parameters/ec_delay
    
    Known machines where this helps:
    Some HP machines where for whatever reasons specific EC accesses take
    very long at resume from S3 (in _WAK function).
    The AE_TIME error is passed upwards and the ACPI interpreter will
    not execute the rest of the _WAK function which results in not properly
    initialized devices/variables with different side-effects.
    
    Afaik, on some MSI machines this helped as well.
    
    If this param is needed there probably are underlying problems like:
      - EC firmware bug
      - A kernel EC driver bug
      - An ACPI interpreter behavior (e.g. timings when specific
        EC accesses happen and how) which the EC does not like
      - ...
    which should get evaluated further, but often are nasty or
    impossible to fix from OS side.
    Signed-off-by: NThomas Renninger <trenn@suse.de>
    Signed-off-by: NLen Brown <len.brown@intel.com>
    7a18e96d
ec.c 26.7 KB