From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frans Klaver Subject: Re: [PATCH 09/16] tty: serial: 8250_dma: Add a TX trigger workaround for AM33xx Date: Fri, 12 Sep 2014 12:28:16 +0200 Message-ID: <20140912102816.GF28458@ci00147.xsens-tech.local> References: <20140911111721.GB17476@xps8300> <54118AAB.2010205@linutronix.de> <5411967A.6090406@hurleysoftware.com> <54119AAA.9080907@linutronix.de> <20140911151114.GD28458@ci00147.xsens-tech.local> <5411C810.7070906@linutronix.de> <2cf997d9-e7de-465b-915d-3a0a5e7b95f7@email.android.com> <54129F6C.7040508@linutronix.de> <20140912094010.GE28458@ci00147.xsens-tech.local> <5412C21A.8020203@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Return-path: Received: from filter1.ibarracuda.nl ([83.247.7.10]:54932 "EHLO filter1.ibarracuda.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751629AbaILK2U (ORCPT ); Fri, 12 Sep 2014 06:28:20 -0400 Content-Disposition: inline In-Reply-To: <5412C21A.8020203@linutronix.de> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Sebastian Andrzej Siewior Cc: Heikki Krogerus , Peter Hurley , tony@atomide.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, balbi@ti.com, linux-serial@vger.kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Alan Cox On Fri, Sep 12, 2014 at 11:51:22AM +0200, Sebastian Andrzej Siewior wrote: > On 09/12/2014 11:40 AM, Frans Klaver wrote: > > > I'm not sure. I just reproduced this on a boneblack, using your uart_v9 > > branch. > > > >> This problem only pops-up if you use DMA. With disabled DMA you don't > >> see this, right? > > > > I get the lockup both with and without DMA enabled. Here's the 8250 > > config I use. Our full .config is attached in case it may provide > > something relevant. > > Hmm. I have a bone black here. Can you tell what you did to get this > lockup? The port configuration (unless 115200 8N1) and what you did to > get this lockup. port config is 115200 8N1. I don't recall doing anything special. I boot, login, less file and get a lock. > > Something that may also help: when I have a lockup on the boneblack, dma > > is enabled and something is written to console like I described earlier, > > I get the following bad irq: > > > Full dmesg is also attached. > > This one should be stuffed by this: > "[RFC] ARM: edma: unconditionally ack the error interrupt" > https://lkml.org/lkml/2014/9/10/714 OK, that makes the console usable again after I write something to kmsg. > > Hope you find something useful in there. > > > Thanks, > > Frans > > Sebastian