• H
    ACPI: thinkpad-acpi: support 16 levels of brightness (v3) · a3f104c0
    Henrique de Moraes Holschuh 提交于
    Lenovo ThinkPads often have 16 brightness levels in EC, and not just eight
    levels like older ThinkPads.  They also have standard ACPI backlight
    brightness control.
    
    We detect the number of brightness levels by the presence of a BCLL package
    with 16 entries.  If BCLL is not there, we assume eight levels (Z6*).  If
    it is there, but it doesn't have 16 entries, we assume eight levels (T60).
    Otherwise we assume sixteen levels (T61, X61, etc).
    
    We don't use _BCL because it can have side-effects in thinkpads.  Thanks to
    Thomas Renninger <trenn@suse.de> for notifying me of this potential
    problem.
    
    Using the standard ACPI backlight brightness control *instead* of the
    native thinkpad backlight control is a better idea, though.  A different
    patch will take care of this.
    Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
    Cc: Thomas Renninger <trenn@suse.de>
    Signed-off-by: NLen Brown <len.brown@intel.com>
    a3f104c0
thinkpad_acpi.c 118.6 KB