From: Zhang Zhen <zhenzhang.zhang@huawei.com>
To: <linux-serial@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Cc: <tim.kryger@linaro.org>, <gregkh@linuxfoundation.org>,
<jamie@jamieiles.com>, <alan@linux.intel.com>, <arnd@arndb.de>,
<shenjiangjiang@huawei.com>, <long.wanglong@huawei.com>
Subject: [RFC] With 8250 Designware UART, if writes to the LCR failed the kernel will hung up
Date: Fri, 6 Mar 2015 17:11:55 +0800 [thread overview]
Message-ID: <54F96F5B.2090601@huawei.com> (raw)
Hi,
I'm testing 4.0-rc1 kernel on my board with 8250 Designware UART.(ARM Cortex-a15 single core).
I found if serial is busy and writes to the LCR failed after tried 1000 times.
The kernel will hung up.
The system boot success after changed from:
95 static void dw8250_serial_out(struct uart_port *p, int offset, int value)
96 {
97 struct dw8250_data *d = p->private_data;
98
...
...
112 writeb(value, p->membase + (UART_LCR << p->regshift));
113 }
114 dev_err(p->dev, "Couldn't set LCR to %d\n", value);
115 }
116 }
to:
95 static void dw8250_serial_out(struct uart_port *p, int offset, int value)
96 {
97 struct dw8250_data *d = p->private_data;
98
...
...
112 writeb(value, p->membase + (UART_LCR << p->regshift));
113 }
114 dev_info(p->dev, "Couldn't set LCR to %d\n", value); //changed here
115 }
116 }
The reason is serial8250_console_write can't get port->lock because serial8250_do_set_termios has
got port->lock.
So i think here we should change from dev_err to dev_info ?
Any suggestions are welcome.
Best regards!
next reply other threads:[~2015-03-06 9:25 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-06 9:11 Zhang Zhen [this message]
2015-03-06 16:50 ` [RFC] With 8250 Designware UART, if writes to the LCR failed the kernel will hung up 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
2015-03-13 15:36 ` Andy Shevchenko
2015-03-15 14:50 ` Peter Hurley
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