tree 56c7b64874b841d925467995dccf915545cde69e
parent 8bf3d4c535c2b9689c2979b281c24e9f59c2f4ad
author Henrique de Moraes Holschuh <hmh@hmh.eng.br> 1245296416 -0300
committer Len Brown <len.brown@intel.com> 1245303035 -0400

thinkpad-acpi: forbid the use of HBRV on Lenovo ThinkPads

Forcing thinkpad-acpi to do EC-based brightness control (HBRV) on a
X61 has very... interesting effects, instead of doing nothing (since
it doesn't have EC-based backlight control), it causes "weirdness" in
the fan tachometer readings, for example.

This means the EC register that used to be HBRV has been reused by
Lenovo for something else, but they didn't remove it from the DSDT.

Make sure the documentation reflects this data, and forbid the user
from forcing the driver to access HBRV on Lenovo ThinkPads.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>