Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932644AbXBNVeE (ORCPT ); Wed, 14 Feb 2007 16:34:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932648AbXBNVeE (ORCPT ); Wed, 14 Feb 2007 16:34:04 -0500 Received: from mail.gurulabs.com ([67.137.148.7]:43410 "EHLO mail.gurulabs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932644AbXBNVeC (ORCPT ); Wed, 14 Feb 2007 16:34:02 -0500 Subject: Re: Linus' laptop and Num lock status From: Dax Kelson To: Linus Torvalds Cc: Jean Delvare , linux-kernel In-Reply-To: References: <1171479361.3706.48.camel@mentorng.gurulabs.com> <20070214202144.1ddb930f.khali@linux-fr.org> Content-Type: text/plain Date: Wed, 14 Feb 2007 14:34:00 -0700 Message-Id: <1171488840.3706.78.camel@mentorng.gurulabs.com> Mime-Version: 1.0 X-Mailer: Evolution 2.8.2.1 (2.8.2.1-3.fc6) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1514 Lines: 41 On Wed, 2007-02-14 at 11:32 -0800, Linus Torvalds wrote: > > On Wed, 14 Feb 2007, 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. > > Heh. Shows just how much I ever used DOS and BIOS. > > > But maybe the first question to ask is: why is the BIOS setting lost in > > the first place? Why is the kernel resetting the led state? > > Ehh. Silly question. "Those flags, they do nothing." > > The kernel needs to know what they are in order to react correctly to > them. And since you can't read them from hardware, the only way to know > what they are (if you don't know about BIOS magic areas) is to SET THEM. > > Which is what the kernel has traditionally always done. Going forward can the kernel peek at 0x497 and follow the BIOS setting? I checked, and looking at offset 0x497 seems to work fine on a couple of systems with USB keyboards. People have long grumbled and complained about the current kernel behavior (1). Dax Kelson (1) http://lkml.org/lkml/1999/2/27/6 http://www.google.com/search?q=linux+num+lock https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=115909 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/