From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030316AbWF0TcS (ORCPT ); Tue, 27 Jun 2006 15:32:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030320AbWF0TcS (ORCPT ); Tue, 27 Jun 2006 15:32:18 -0400 Received: from atlrel8.hp.com ([156.153.255.206]:9098 "EHLO atlrel8.hp.com") by vger.kernel.org with ESMTP id S1030316AbWF0TcR (ORCPT ); Tue, 27 Jun 2006 15:32:17 -0400 Subject: Re: [PATCH] 8250 UART backup timer From: Alex Williamson To: "H. Peter Anvin" Cc: rmk+serial@arm.linux.org.uk, linux-kernel In-Reply-To: <44A183C5.6050002@zytor.com> References: <1151435054.11285.41.camel@lappy> <44A183C5.6050002@zytor.com> Content-Type: text/plain Organization: OSLO R&D Date: Tue, 27 Jun 2006 13:32:11 -0600 Message-Id: <1151436731.5600.50.camel@lappy> Mime-Version: 1.0 X-Mailer: Evolution 2.6.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2006-06-27 at 12:15 -0700, H. Peter Anvin wrote: > Alex Williamson wrote: > > The patch below works around a minor bug found in the UART of the > > remote management card used in many HP ia64 and parisc servers (aka the > > Diva UARTs). The problem is that the UART does not reassert the THRE > > interrupt if it has been previously cleared and the IIR THRI bit is > > re-enabled. This can produce a very annoying failure mode when used as > > a serial console, allowing a boot/reboot to hang indefinitely until an > > RX interrupt kicks it into working again (ie. an unattended reboot could > > stall). > > I have seen this same bug in soft UART IP from "a major vendor." If you get a chance to try, please let us know if this patch works there too or needs any additional tweaking to make it work there. Thanks, Alex -- Alex Williamson HP Open Source & Linux Org.