void sn_sal_console_write (struct console * co, const char * s, unsigned count);
This is referenced in the console struct. It is used for early console printing before we register with serial core and for things such as kdb. The console_lock must be held when we get here.
This function has some code for trying to print output even if the lock is held. We try to cover the case where a lock holder could have died. We don't use this special case code if we're not registered with serial core yet. After we're registered with serial core, the only time this function would be used is for high level kernel output like magic sys req, kdb, and printk's.