From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756890AbYDULLX (ORCPT ); Mon, 21 Apr 2008 07:11:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754510AbYDULLQ (ORCPT ); Mon, 21 Apr 2008 07:11:16 -0400 Received: from smtp.seznam.cz ([77.75.72.43]:46004 "HELO smtp.seznam.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753956AbYDULLP (ORCPT ); Mon, 21 Apr 2008 07:11:15 -0400 X-Greylist: delayed 401 seconds by postgrey-1.27 at vger.kernel.org; Mon, 21 Apr 2008 07:11:15 EDT From: "Frantisek Rysanek" To: linux-kernel@vger.kernel.org Date: Mon, 21 Apr 2008 13:12:41 +0200 MIME-Version: 1.0 Subject: What pokes the ISA IO port of 0x211 ? Message-ID: <480C92C9.18283.A24BB91B@localhost> X-mailer: Pegasus Mail for Windows (4.21c) Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Content-description: Mail message body X-Smtpd: 1.0.36@12969 X-Seznam-User: frantisek.rysanek@post.cz Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dear Everyone, I'm dealing with an embedded PC motherboard that contains some custom circuitry (GPIO), accessible via an ISA IO range between 0x200 and 0x218. There's an interesting issue with this in recent Linux (tried 2.6.22.6 and 2.6.24.2): something probes IO port 0x211 on boot, which happens to be an add-on buzzer control port - effectively the kernel boot launches an accoustic alarm :-) Any ideas what this could be? Obviously it's no problem for me to write a tiny kernel module to disable the alarm again, and I've actually verified the problem using ioperm()+outb() from user space, but still I'd be interested to know which particular piece of code could be probing that address... The address decode might be implemented using some general-purpose features of the Winbond W83627HF SuperIO (as there's no ISA in the system, just ICH4 LPC) - but it seems quite unlikely that this would be caused by something fiddling with the W83627 config registers. It really seems like something writes 0xFF to IO port 0x211. Thanks for your time and attention :-) Frank Rysanek