Re: Linus' laptop and Num lock status

From: H. Peter Anvin
Date: Sun Feb 18 2007 - 12:32:52 EST

Jean Delvare wrote:
On Thu, 15 Feb 2007 06:34:35 -0800, H. Peter Anvin wrote:
Jean Delvare wrote:
On x86, the BIOS led state can be read from byte 0x97 the BIOS RAM. The
BIOS RAM is mapped at 0x400 so all we need to do is to one byte from
RAM (offset 0x497). This is how Suse's hwinfo does.
Perhaps that's what Suse does, but the proper address is 0x417.

0x497 is the rarely-used LPT2 timeout counter.

Still, the information printed by hwinfo is correct, I've tested it
myself. Is there some publicly available documentation about the x86
BIOS RAM mapping?

Google for Ralf Brown's Interrupt List.

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