While helping a user find out what happened to his mute key, I found out that the Lenovo BIOSes need the OSI string Linux defined to behave properly in Linux. Lenovo has been attempting to make things a bit easier for Linux on their ThinkPads, by disabling the more obnoxious behaviours of the firmware (used by their Windows drivers) when in Linux. It looks like they used the OSI string for that. It is probably worthwhile to give a head's up: regressions involving thinkpads and 2.6.23+ should probably have a 'please test with acpi_osi="Linux"' step added if there is any chance ACPI AML code, BIOS or SMBIOS code, or EC behaviour could be involved. The most concrete example I have right now of changed behaviour is the Mute key on the T61, which just plain disappears if acpi_osi="!Linux" (2.6.23 default). I have also seen some hacked DSDTs around (mostly for older T4x models) which used the Linux OSI string to fix or work around AML weirdness. Those would break in 2.6.23 (and 2.6.24?) as well. Now, what should we do about it? Add a quirk to always define the Linux OSI string on ThinkPads (based on DMI information)? All IBM ones (which won't have BIOS revisions anymore, anyway) deal well with it, and Lenovo ones seem to benefit from it. We could also ask Lenovo to change the BIOS to stop paying attention to that OSI string, but they will likely want/need a trigger for the AML code to know it should change behaviour anyway, and the OSI string *does* look like the proper thing to use IMHO. I don't know if we could get them to arrive to a behaviour that is acceptable both to us, and also to their Windows drivers... -- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh - 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
