From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S275309AbTHMSe2 (ORCPT ); Wed, 13 Aug 2003 14:34:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S275317AbTHMSe2 (ORCPT ); Wed, 13 Aug 2003 14:34:28 -0400 Received: from caramon.arm.linux.org.uk ([212.18.232.186]:31755 "EHLO caramon.arm.linux.org.uk") by vger.kernel.org with ESMTP id S275309AbTHMSe1 (ORCPT ); Wed, 13 Aug 2003 14:34:27 -0400 Date: Wed, 13 Aug 2003 19:34:18 +0100 From: Russell King To: Geert Uytterhoeven Cc: Linux Kernel Development , Linux/PPC Development Subject: Re: Bogus serial port ttyS02 Message-ID: <20030813193418.D20676@flint.arm.linux.org.uk> Mail-Followup-To: Geert Uytterhoeven , Linux Kernel Development , Linux/PPC Development References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: ; from geert@linux-m68k.org on Wed, Aug 13, 2003 at 05:40:23PM +0200 X-Message-Flag: Your copy of Microsoft Outlook is vulnerable to viruses. See www.mutt.org for more details. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 13, 2003 at 05:40:23PM +0200, Geert Uytterhoeven wrote: > Linux always finds 3 serial ports instead of 2: > > | ttyS00 at 0x03f8 (irq = 4) is a 16550A > | ttyS01 at 0x02f8 (irq = 3) is a 16550A > | ttyS02 at 0x03e8 (irq = 4) is a 16450 > > The last one is bogus. Do you know that it absolutely does not exist? Can it exist on any PPC box? If the answer to both those questions is no, I suggest you don't probe for it in the first place. You could enable DEBUG_AUTOCONF in 8250.c in 2.6.0-test3 and give further probing information. 8) Looking at PPC's pc_serial.h, it seems that you've told it to probe there using ASYNC_BOOT_AUTOCONF | ASYNC_SKIP_TEST | ASYNC_AUTO_IRQ. ASYNC_SKIP_TEST means that we use a reduced test to probe for a port - we just check that we can read back a value written to 0x3e9. If this suceeds, we decide that there is a port present, and go on to try and derive its type. If you want to enable the more rigorous tests, remove ASYNC_SKIP_TEST from the port flags. This will make us check that the device behaves like a UART before deciding that it is one. -- Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux http://www.arm.linux.org.uk/personal/aboutme.html