Subject: Re: Documentation for the wsscroll patch
To: Pavel Cahyna <>
From: David Ferlier <>
List: tech-kern
Date: 01/28/2003 14:08:41
On Tue, Jan 28, 2003 at 10:05:48AM +0100, Pavel Cahyna wrote:
> Hello,
> you write that it's for i386 only, but the files affected by the patch

I said i386, cause i just tested it on i386, but it can work on any machine
with a vga card.

> are all machine-independent. Why?

The api is machine-independent: in fact, it adds a function to the
wsdisplay_accessops structure.

Each display device driver that attaches to a wsdisplay device and which
supports scrolling just has to put a pointer to a function in its
wsdisplay_accessops (see the file vga.c my patch modifies). When you press
a key whose command is one of the Cmd_Scroll* commands i added,
wskbd_translate calls wskbd_command. This function calls the scroll function
with the good arguments (number of lines).

If the scroll function's pointer of the wsdisplay_accessops of the driver is
not null it calls it, and it calls a low-level md function (for vga, it's

So the interface is machine-independant. Device displays who can't scroll
just have to put a null pointer for scroll.

> If you make a version which will work on 1.6_STABLE, I probably could
> try it on an alpha.

It works on 1.6_STABLE (i tested it on a friend's machine).

Thanks for asking that, i'll modify the documentation.


> Bye	Pavel


David Ferlier	-	- Of Course It Runs NetBSD