Subject: Console: Basic Kernel Interface Point
To: None <>
From: anand lalgondar <>
List: tech-kern
Date: 11/05/2003 12:33:11

Can anyone tell me how the following modules are related:
1. cntab
2. consdev
3. consinit function call.

I know that these are kernel interface point to Input/Ouput for NetBSD. But 

At present one of my target boards support serial terminal console (both 
input and output). Now if I want to support a graphcis card "as Ouput 
device", leaving the serial port "as input device" what should be done. What 
are the kernel interface point and how to modify them.

At present my serial port driver has initlaization code for the consdev as:
static struct consdev txsio_cons = {
	NULL, NULL, txsio_cngetc, txsio_cnputc, txsio_cnpollc, NULL, NODEV,
and I am sure this is used to support the basic Input/Output for the console 
- Terminal.

What changes are to be made to support Graphics card as Output. One more 
important point is the Graphics card should be completely initialized from 
scratch, PMON (BIOD) does not support that.

Can we change the console output device when the kernel is up and running, 
i.e switching from serial port to graphics card.

I have browsed through the sparc code "kd.c", but without having a base idea 
I could not go further.

Can anyone help me in this issue.

Thanks anyways.

- Anand

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