分类: 嵌入式
2013-10-23 15:24:34
原文地址:/bin/sh: can 作者:ztguang
BusyBox通过系统控制台来做些工作, 如果我们的shell启动在 /dev/console(5,1)上, tty_io.c 函数open中noctty就被设置成1,导致这个问题,具体原因还不知道。总之要启动在一个真实的串口就没有关系。
Job control will be turned off since your shell can not obtain a controlling terminal. This typically happens when you run your shell on /dev/console. The kernel will not provide a controlling terminal on the /dev/console device. Your should run your shell on a normal tty such as tty1 or ttyS0 and everything will work perfectly. If you REALLY want your shell to run on /dev/console, then you can hack your kernel (if you are into that sortof thing) by changing drivers/char/tty_io.c to change the lines where it sets "noctty = 1;" to instead set it to "0". I recommend you instead run your shell on a real console...解决方法
可以通过BusyBox的init指定shell的设备, 注意, S3C2410上, 串口0是s3c2410_serial0。也就是说去掉::respawn:-/bin/sh就可以啦~~
串口名称可以是s3c2410_serialx、ttySACx和ttySx等,但底层使用的是设备的主设备号和次设备号来定位具体设备的。所以不管是串口的名称是什么,只要主设备号和次设备号对了就可以。此外,通过mdev生成设备节点时,串口的名称是s3c2410_serialx。S3C2410的串口驱动文件drivers/serial/s3c2410.c中,有如下数据结构:[plain] view plaincopy static struct uart_driver s3c24xx_uart_drv = { .owner = THIS_MODULE, .dev_name = "s3c2410_serial", .nr = 3, .cons = S3C24XX_SERIAL_CONSOLE, .driver_name = S3C24XX_SERIAL_NAME, .major = S3C24XX_SERIAL_MAJOR, // 主设备号为204 .minor = S3C24XX_SERIAL_MINOR, // 次设备号为64,这指第1个串口;第2个为65 };通过这个结构体就可以确定串口设备的主设备号和次设备号。