Hope I can contribute and sorry for the interruption of conversation :-(.
Happy Hacking.....
--
Regards,
Peter Teoh
On Tue, Jan 10, 2012 at 2:59 PM, Dave Hylands <dhylands@xxxxxxxxx> wrote:
Hi sandeep,
A console is where the output from printk goes.
On Mon, Jan 9, 2012 at 10:37 PM, sandeep kumar
<coolsandyforyou@xxxxxxxxx> wrote:
> Hi All,
>
> I want to know "What is a console?
> and Why it is always associated with
> UART?"
Yes, console is output and UART is the hardware device input port.....it can be implemented hardware wise by many different devices, but all of them will speak the UART protocol:
and the hardware devices' source codes are in drivers/tty/serial/8250_xxxxx.c for examples (xxxx for different devices).
�
While console's may often be associated with a UART (typical for
embedded systems) there is no need or requirement for them to be
associated with a console. You can regitser a console to send the
output wherever you like.
A serial console is a console driver (registered via register_console)
> What is a serial console??
which sends the output to a serial port, typically also allowing the
serial port to be used as a tty interface.
Sure. I don't know if a driver for this exists yet, but if it doesn't
> Can there be a USB console??
you can always write one.
According to the diagram of the book "Essential Linux Device Drivers" page 175, both the output of serial_core.c and usb-serial.c (which implements the serial signals coming in from the USB interface) are directed to n_tty.c (which essentially goes to the serial console output). � So answer is NO, current architecture has the tty console linked to both UART and USB-Serial interface. � (a FTDI software driver drivers/usb/serial/ftdi_sio.c is needed to convert the USB signal back to the serial packets structure). ��
�
There is already something called a netconsole (see
Documentation/networking/netconsole.txt). This is an example of a
console which isn't associated with a serial port.
There is also a framebuffer console (See Documentation/fb/fbcon.txt)
--
Dave Hylands
Shuswap, BC, Canada
http://www.davehylands.com
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Regards,
Peter Teoh
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