linux-kernel - Re: Linus' laptop and Num lock status

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Message-Id: <1171480780.3706.56.camel@mentorng.gurulabs.com>
Date:	Wed, 14 Feb 2007 12:19:40 -0700
From:	Dax Kelson <dax@...ulabs.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	linux-kernel <linux-kernel@...r.kernel.org>,
	Jean Delvare <khali@...ux-fr.org>
Subject: Re: Linus' laptop and Num lock status

On Wed, 2007-02-14 at 11:12 -0800, Linus Torvalds wrote:
> 
> On Wed, 14 Feb 2007, Dax Kelson wrote:
> > 
> > Are there any technical or political reasons why kernel can't change
> > from "force off" to "Follow BIOS"?
> 
> How would you query it? I'm not even 100% sure that you can on all 
> keyboards. We never query the leds, we always set them. I think. I don't 
> know of any AT kbd command to read the led state out of the keyboard.
> 
> 		Linus

The GPL'd "hwinfo" command shipped with SUSE queries the BIOS setting by
reading a single byte from /dev/mem.

In src/hd/bios.c around line 262 it has:

  if(hd_data->bios_ram.data) {
    bios_ram = hd_data->bios_ram.data;

[snip]

    bt->led.scroll_lock = bios_ram[0x97] & 1;
    bt->led.num_lock = (bios_ram[0x97] >> 1) & 1;
    bt->led.caps_lock = (bios_ram[0x97] >> 2) & 1;
    bt->led.ok = 1;


Cut-n-paste commands to get to the source:

cd /tmp
wget http://ftp.opensuse.org/pub/opensuse/distribution/SL-OSS-factory/inst-source/suse/src/hwinfo-13.21-3.src.rpm
rpm2cpio < hwinfo-13.21-3.src.rpm | cpio -id
tar jxf hwinfo-13.21.tar.bz2
cd hwinfo-13.21/src/hd

Dax Kelson

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