hi yang, 在 2012年3月10日 下午10:37，yang gqyang <[email protected]> 写道： > Thanks for your comment. > Finally, i find out that i made a mistake. The uart(8250) have not been > restore after resume, instead, it use the configuration got from boot. The > uart have not been restored correctly, so that "ls" can not output result > correctly resulting in it seems that the busybox can not work correctly. > Now, i still have a question about the uart: why the "printk" can work > correctly, but the "printf" not? > > Before this, i believe that the "printk" work correctly, then the uart > work ok. but now, i need more reconsidaration about > the relation between the "printk", "printf" and "uart". > Can anyone give me some suggestion? Any comment is welcome, thanks a > lot.
printk use "struct console" driver, it doesn't depend on a device node for userspace. printf actaully depends on uart_driver and a /dev/ttySx device node, stdout and stderr are redirected to /dev/ttySx uart is just a hardware which can be a tty or kernel console output. > > -barry -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
