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From: Zhang Zhen <zhenzhang.zhang@huawei.com>
To: Peter Hurley <peter@hurleysoftware.com>
Cc: Tim Kryger <tim.kryger@gmail.com>,
	Alan Cox <alan@linux.intel.com>,
	"long.wanglong" <long.wanglong@huawei.com>,
	<linux-serial@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	<gregkh@linuxfoundation.org>, Jamie Iles <jamie@jamieiles.com>,
	Arnd Bergmann <arnd@arndb.de>, <shenjiangjiang@huawei.com>,
	Wang Kai <morgan.wang@huawei.com>
Subject: Re: [RFC] With 8250 Designware UART, if writes to the LCR failed the kernel will hung up
Date: Wed, 11 Mar 2015 09:20:19 +0800	[thread overview]
Message-ID: <54FF9853.2060105@huawei.com> (raw)
In-Reply-To: <54FEF0B0.6010002@hurleysoftware.com>

On 2015/3/10 21:25, Peter Hurley wrote:
> On 03/09/2015 10:47 PM, Tim Kryger wrote:
>> The current workaround of clearing fifos and retrying a fixed number
>> of times isn't ideal but I'm not sure what else can be done given the
>> way this hardware works.
> 
> But hanging the machine is not an acceptable outcome.
> 
> Since the hang stems from the printk while already holding the port->lock,
> until I can fix the console write, I think it's best to comment out
> the dev_err() with a FIXME note.

Yeah,i agree.
> 
> The 8250 console write already checks port->sysrq to allow printk from
> within the driver so this solution just needs to be generalized.
> And there are debug uses of printk() from within the driver that are just
> as broken, so this isn't the only use case. (I want to do something
> similar for the au_serial-* i/o accessors too).
> 
> Regards,
> Peter Hurley
> 
> 
> 
> .
> 



  reply	other threads:[~2015-03-11  1:20 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-06  9:11 Zhang Zhen
2015-03-06 16:50 ` Peter Hurley
2015-03-07  3:01   ` Tim Kryger
2015-03-09  7:10     ` long.wanglong
2015-03-09 13:32       ` Alan Cox
2015-03-09 14:36         ` Tim Kryger
2015-03-09 15:05           ` Alan Cox
2015-03-10  2:47             ` Tim Kryger
2015-03-10  3:15               ` Zhang Zhen
2015-03-10 13:25               ` Peter Hurley
2015-03-11  1:20                 ` Zhang Zhen [this message]
2015-03-13 15:36               ` Andy Shevchenko
2015-03-15 14:50                 ` Peter Hurley

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