From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754725AbcDAL15 (ORCPT ); Fri, 1 Apr 2016 07:27:57 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:19765 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751513AbcDAL1z (ORCPT ); Fri, 1 Apr 2016 07:27:55 -0400 Subject: Re: [PATCH] serial: 8250_dw: fix wrong logic in dw8250_check_lcr() To: Andy Shevchenko , Noam Camus , Greg Kroah-Hartman References: <1459501618-21021-1-git-send-email-wangkefeng.wang@huawei.com> <1459504683.5907.151.camel@linux.intel.com> CC: Heikki Krogerus , , , , From: Kefeng Wang Message-ID: <56FE4B2E.30305@huawei.com> Date: Fri, 1 Apr 2016 18:19:26 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <1459504683.5907.151.camel@linux.intel.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.19.180] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020203.56FE5B16.01A0,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: ac4393e7be053c91103c97f577056561 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2016/4/1 17:58, Andy Shevchenko wrote: > On Fri, 2016-04-01 at 17:06 +0800, Kefeng Wang wrote: >> Commit cdcea058e510("serial: 8250_dw: Avoid serial_outx code >> duplicate >> with new dw8250_check_lcr()") introduce a wrong logic when write val >> to >> LCR reg. When CONFIG_64BIT enabled, __raw_writeq is used >> unconditionally. >> >> But for !PORT_OCTEON, we better to use coincident write func. >> >> Signed-off-by: Kefeng Wang >> --- >> >> We met following calltrace twice, if the change is not necessary, >> correct me, >> and any advice will be appreciated, thanks. > > So, does this fix you issue? If it does than perhaps you need to Cc > stable@ and put Fixes tag as well. We only met this issue twice, for now it is ok, and I will do more test with this patch. > >> --- a/drivers/tty/serial/8250/8250_dw.c >> +++ b/drivers/tty/serial/8250/8250_dw.c >> @@ -104,15 +104,16 @@ static void dw8250_check_lcr(struct uart_port >> *p, int value) >> dw8250_force_idle(p); >> >> #ifdef CONFIG_64BIT >> - __raw_writeq(value & 0xff, offset); >> -#else >> + if (p->type == PORT_OCTEON) >> + __raw_writeq(value & 0xff, offset); >> + else >> +#endif > > You may also get rid of this one, like > > if (IS_ENABLED(CONFIG_64BIT) && p->type == PORT_OCTEON) > ... > else if > ... Agree. > >> if (p->iotype == UPIO_MEM32) >> writel(value, offset); >> else if (p->iotype == UPIO_MEM32BE) >> iowrite32be(value, offset); >> else >> writeb(value, offset); >> -#endif >> } >> /* >> * FIXME: this deadlocks if port->lock is already held >