Johnny Hung <johnny.hacking <at> gmail.com> writes: > > Hi All: > I have a powerpc arch platform. The default console is ttyS1 not > ttyS0 in the platform. My question is how the kernel print debug > message > like DBG before parse kernel command line and do console_setup > function. The command line passed to kernel about console info is > console=ttyS1. > So kernel can not print anything before parse cmd line and initial > console but the result is against. Anyone point me or give me a clue > is appreciate. > > BR, H. Johnny > Don't worry, printk uses a ring buffer so it allows the kernel to print some, hopefully enough, out before console is registered/initialized. This is from printk.c 197 /* 198 * The console driver calls this routine during kernel initialization 199 * to register the console printing procedure with printk() and to 200 * print any messages that were printed by the kernel before the 201 * console driver was initialized. 202 */ 203 void register_console(void (*proc)(const char *)) Freeman -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
