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
next prev parent 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 [RFC] With 8250 Designware UART, if writes to the LCR failed the kernel will hung up 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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