Hi sandeep, On Tue, May 17, 2011 at 12:52 AM, sandeep kumar <[email protected]> wrote: > > Hi , > Here is my question. > when we put 'printk's in kernel code the logs will go to the log_buffer.(i > observed that from implementation) > But when UART is enabled(in the bootloader), the same printk logs are going > to the serial console. > As per my study printk doesnot implementing anything that writes to the UART > console. > > Now here are my questions, > how this is being achieved? Where this is implemented?(which file)
When you register your UART driver there is typically an option to register a console driver at the same time. For example, let's take a look at the 8250 serial driver. We'll look at the file drivers/serial/8250.c Search for the function serial8250_console_init, which has a call to register_console. That's the starting point that sets up the console driver. You can have other drivers call register_console and get your console messages sent out whatever bizarre device you may have connected to your system. You can also have multiple consoles registered at the same time. > Where wil be the parsing of the cmdline string sent from the bootloader is > done? The function console_setup is called when the console= parameter is passed on the kernel command line. <http://lxr.linux.no/linux+v2.6.38/kernel/printk.c#L904> The __setup just after the end of the function is what causes it to call that function when the console= parameter is passed. -- Dave Hylands Shuswap, BC, Canada http://www.davehylands.com _______________________________________________ Kernelnewbies mailing list [email protected] http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
