Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262687AbVENGoW (ORCPT ); Sat, 14 May 2005 02:44:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262689AbVENGoW (ORCPT ); Sat, 14 May 2005 02:44:22 -0400 Received: from fire.osdl.org ([65.172.181.4]:20151 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S262687AbVENGoQ (ORCPT ); Sat, 14 May 2005 02:44:16 -0400 Date: Fri, 13 May 2005 23:43:31 -0700 From: Andrew Morton To: Dave Jones Cc: linux-kernel@vger.kernel.org Subject: Re: tickle nmi watchdog whilst doing serial writes. Message-Id: <20050513234331.0d097cb1.akpm@osdl.org> In-Reply-To: <20050513184806.GA24166@redhat.com> References: <20050513184806.GA24166@redhat.com> X-Mailer: Sylpheed version 1.0.0 (GTK+ 1.2.10; i386-vine-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1541 Lines: 45 Dave Jones wrote: > > This was fun. I inserted a music CD with some obnoxious copy-protection > on it into the drive, and lots of SCSI errors went zipping over to > the serial console. Unfortunatly, the box was also compiling a kernel, > playing oggs, and doing a number of other things at the same time, > so this happened.. > > NMI Watchdog detected LOCKUP on CPU2CPU 2 OK.. But calling touch_nmi_watchdog() at 1MHz seems a bit excessive, and might perturb the finely-tuned timing in there. How's about this? --- 25/drivers/serial/8250.c~tickle-nmi-watchdog-whilst-doing-serial-writes 2005-05-13 23:37:57.000000000 -0700 +++ 25-akpm/drivers/serial/8250.c 2005-05-13 23:41:36.000000000 -0700 @@ -40,6 +40,7 @@ #include #include #include +#include #include #include @@ -2098,9 +2099,10 @@ static inline void wait_for_xmitr(struct /* Wait up to 1s for flow control if necessary */ if (up->port.flags & UPF_CONS_FLOW) { tmout = 1000000; - while (--tmout && - ((serial_in(up, UART_MSR) & UART_MSR_CTS) == 0)) + while (!(serial_in(up, UART_MSR) & UART_MSR_CTS) && --tmout) udelay(1); + if (tmout < 1000000) + touch_nmi_watchdog(); } } _ - 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/