Lots of that ACPI incompatibility isn't stupidity on the behalf of the vendors is "non-aggressive" linux lock-out.
Take Toshiba for example. Most of their recent laptops have an ACPI "bug" where the fans are reported as always being on. This causes no end of overheat hell for me. I decompiled, fixed and then loaded a patched DSDT table into mine to fix this. From what I can tell Windows just ignores the current state and toggles the fans as it sees fit.
Anyway here is a link for those who haven't seen it to prove I'm not wearing tin-foil hats http://antitrust.slated.org/www.iowaconsumercase.org/011607/3000/PX03020.pdf
Re: HCL?
Take Toshiba for example. Most of their recent laptops have an ACPI "bug" where the fans are reported as always being on. This causes no end of overheat hell for me. I decompiled, fixed and then loaded a patched DSDT table into mine to fix this. From what I can tell Windows just ignores the current state and toggles the fans as it sees fit.
Anyway here is a link for those who haven't seen it to prove I'm not wearing tin-foil hats
http://antitrust.slated.org/www.iowaconsumercase.org/011607/3000/PX03020.pdf