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From: Alan Cox <alan@linux.intel.com>
To: Tim Kryger <tim.kryger@gmail.com>
Cc: "long.wanglong" <long.wanglong@huawei.com>,
	Peter Hurley <peter@hurleysoftware.com>,
	Zhang Zhen <zhenzhang.zhang@huawei.com>,
	linux-serial@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Tim Kryger <tim.kryger@linaro.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: Mon, 09 Mar 2015 15:05:02 +0000	[thread overview]
Message-ID: <1425913502.3838.185.camel@linux.intel.com> (raw)
In-Reply-To: <CAD7vxxJvL61BjD9AMBF34Y8xnY+D-umuWLUq8Dh7ZbSm5tCE9w@mail.gmail.com>

On Mon, 2015-03-09 at 07:36 -0700, Tim Kryger wrote:
> On Mon, Mar 9, 2015 at 6:32 AM, Alan Cox <alan@linux.intel.com> wrote:
> >> Maybe the next release of the board we will upgrade the serial block to the new version.
> >> but the issue is that how we circumvent this problem in kernel?
> >
> > What is the official vendor workaround ?
> 
> They introduced a UART_16550_COMPATIBLE option for the IP which should
> be selected.
> 
> If configured, writes to the LCR are allowed even if it is "busy" so
> there is no need to retry.
> 
> More importantly there is no possibility of failing to write the LCR
> after numerous retries.


Ah no - I meant what is their official software workaround for existing
parts with the bug ? Presumably they have an errata document that
discusses this and the correct methods they recommend to avoid the
hang ?

Alan



  reply	other threads:[~2015-03-09 15:05 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 [this message]
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
2015-03-13 15:36               ` Andy Shevchenko
2015-03-15 14:50                 ` Peter Hurley

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