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| author | Henrique de Moraes Holschuh <hmh@hmh.eng.br> | 2008-04-26 01:02:21 -0300 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2008-04-29 09:47:01 -0400 |
| commit | e11aecf1379e7c4a0293182096e38e5a336696b2 (patch) | |
| tree | 9dfc915ef98293b7a7b3e42b7a5de9797b0ceb29 /Documentation/laptops/thinkpad-acpi.txt | |
| parent | 2d5e94d7ca315f859a0eee1366838e8ad34dd7b2 (diff) | |
| download | blackbird-op-linux-e11aecf1379e7c4a0293182096e38e5a336696b2.tar.gz blackbird-op-linux-e11aecf1379e7c4a0293182096e38e5a336696b2.zip | |
ACPI: thinkpad-acpi: fix brightness dimming control bug
ibm-acpi and thinkpad-acpi did not know about bit 5 of the EC backlight
level control register (EC 0x31), so it was always forced to zero on
any writes.
This would disable the BIOS option to *not* use a dimmer backlight level
scale while on battery, and who knows what else (there are two other
control bits of unknown function).
Bit 5 controls the "reduce backlight levels when on battery" optional
functionality (active low). Bits 6 and 7 are better left alone as well,
instead of being forced to zero.
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'Documentation/laptops/thinkpad-acpi.txt')
0 files changed, 0 insertions, 0 deletions
