lkml.org 
[lkml]   [2006]   [Jan]   [31]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
/
FromJindrich Makovicka <>
SubjectRe: [PATCH] vgacon: Add support for soft scrollback
DateTue, 31 Jan 2006 07:58:49 +0100
Antonino A. Daplas wrote:
> The scrollback buffer of the VGA console is located in VGA RAM. This
> RAM is fixed in size and is very small. To make the scrollback buffer
> larger, it must be placed instead in System RAM.> > This patch adds this feature.  The feature and the size of the buffer
> are made as a kernel config option.  Besides consuming kernel memory,
> this feature will slow down the console by approximately 20%.
> > Signed-off-by: Antonino Daplas <adaplas@pol.net>
> ---
> 
> This patch is the result of a discussion on how to capture very long
> oops tracings.  One of the suggestions was to increase the size of
> the scrollback buffer of the VGA console.
> 
> I haven't tested the code rigorously, so let me know of any bugs. I
> also tried to make it behave as close as possible to vgacon with a hard
> scrollback.

[...]

> +static int vgacon_scrolldelta(struct vc_data *c, int lines)
> +{> +	if (!lines)		/* Turn scrollback off */> +		c->vc_visible_origin = c->vc_origin;> +	else {> +		int margin = c->vc_size_row * 4;> +		int ul, we, p, st;> +> +		printk("vgacon delta: %i\n", lines);

                ^^^^^^
This disables the hard scrollback, as the console is immediately
scrolled back when the mesage gets printed.
Regards,
-- 
Jindrich Makovicka

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-01-31 08:01    [from the cache]
©2003-2008