On Thu, 2009-08-20 at 17:14 +0800, Stefan Bader wrote: > Hardware: Acer 6920G (from a bug report) > > Another case of a broken BIOS. In this case there are several definitions for > video bus devices but only one has _DOS and _DOD defined. All other definitions > only have _DOD. I have seen such kind of BIOS too. > In the past (2.6.27) _ADR was not evaluated to make sure of using a present > video device, but with that bug brightness could be changed. > > Now the video bus having _DOS and _DOD is detected as not being present. The > other definitions are not considered because they are lacking the _DOS method. > Using the attached patch, would cause the detection code to consider the other > definitions and has been tested to enable backlight control. > > Would this be an acceptable approach? I think so. I generated a similar patch before, but didn't sent it out for some reason. My suggestion is that we should also print out a warning message if _DOS is missed, what do you think? thanks, rui > From the ACPI spec it rather sounds like > _DOD and _DOS must be present for a device for display switching and _DOS would > indicate possible backlight control as well. So the question might not be so > much is it the right thing than is it safe enough to allow more compatibility > with broken implementations without causing other problems... > > -Stefan > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
