From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from na01-by2-obe.outbound.protection.outlook.com (mail-by2lp0236.outbound.protection.outlook.com [207.46.163.236]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id C22572C00D0 for ; Tue, 18 Feb 2014 06:37:14 +1100 (EST) Message-ID: <1392665821.6733.630.camel@snotra.buserror.net> Subject: Re: Anyone using SysRQ key sequences on console serial port ? From: Scott Wood To: Paul Gortmaker Date: Mon, 17 Feb 2014 13:37:01 -0600 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Cc: John Donnelly , linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sun, 2014-02-16 at 10:56 -0500, Paul Gortmaker wrote: > On Fri, Feb 14, 2014 at 3:42 PM, John Donnelly wrote: > > Hi, > > > > I tried using the SysRq hotkey sequence on a serial console - > > 3.11.0-5-powerpc-e500mc system, by issuing a " break " and the system > > immediately wedges after displaying "SysRQ : HELP : " using both "Putty" and > > "Teraterm" terminal emulators. I know the system is dead because my ssh > > sessions stopped too. > > Yes it does work -- or at least it _did_ work. Make sure your dts has an entry > > compatible = "fsl,ns16550", "ns16550"; > > since that enables a workaround I'd added for a hardware errata relating > to sending breaks over the serial console. What you describe above > makes me think you aren't getting the workaround enabled. Also make sure CONFIG_SERIAL_8250_FSL is enabled. -Scott