Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757709AbXIUNoU (ORCPT ); Fri, 21 Sep 2007 09:44:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758871AbXIUNn4 (ORCPT ); Fri, 21 Sep 2007 09:43:56 -0400 Received: from caramon.arm.linux.org.uk ([78.32.30.218]:34062 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758788AbXIUNnz (ORCPT ); Fri, 21 Sep 2007 09:43:55 -0400 Date: Fri, 21 Sep 2007 14:43:32 +0100 From: Russell King To: "Maciej W. Rozycki" Cc: Andrew Morton , Gerd Hoffmann , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Yinghai.Lu@Sun.COM, bryan.wu@analog.com, dilinger@queued.net, kraxel@redhat.com, lethal@linux-sh.org, rgetz@blackfin.uclinux.org, vapier.adi@gmail.com Subject: Re: [PATCH] kernel/printk.c: Concerns about the console handover Message-ID: <20070921134331.GC20277@flint.arm.linux.org.uk> References: <20070921010349.2caee558.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1686 Lines: 38 On Fri, Sep 21, 2007 at 02:36:50PM +0100, Maciej W. Rozycki wrote: > On Fri, 21 Sep 2007, Andrew Morton wrote: > > > It would be useful to have some basic information like: Which kernel > > version was this found in? Which kernel version last worked? > > The kernel used was a 2.6.23-rc5 snapshot from Sep 4th, 2007 taken from > the linux-mips.org tree (as stated by the revision of the patch provided). > There is no version that can be considered working as the change to add > the printk() to register_console() went in before drivers/serial/zs.c was > added and the old drivers/tc/zs.c driver might have been to sloppy to > handle such bits as the transmitter enable properly. I may investigate. > > Chances are nobody tried any version of the kernel from the period > between the printk() was added and drivers/tc/zs.c removed with the > DECstation; I have not. > > Anyway, I did confirm keeping the transmitter enabled all the time makes > the problem go away. I suspect the correct fix for this is to take the fix in the ARM tree for serial_core's console initialisation, and ensure that zs.c handles the power management of the port (enabling/disabling transmitter) in the power management callback. You can find the fix in the mbox archive: http://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cut/arm:devel.mbox -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: - 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/