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 <[email protected]>
> ---
>
> 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
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