On Tue, 2008-01-08 at 21:19 -0800, H. Peter Anvin wrote: > Zachary Amsden wrote: > > > > BTW, it isn't ever safe to pass port 0x80 through to hardware from a > > virtual machine; some OSes use port 0x80 as a hardware available scratch > > register (I believe Darwin/x86 did/does this during boot). > > That's funny, because there is definitely no guarantee that you get back > what you read (well, perhaps there is on Apple.)
According to Phoenix Technologies book "System BIOS for IBM PCs, Compatibles and EISA Computers, 2nd Edition", the I/O port list gives port 0080h R/W Extra page register (temporary storage) Despite looking, I've never seen it documented anywhere else, but I believe it works on just about every PC platform. Except, apparently, my laptop. Zach -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
