On Mon, Apr 5, 2021, 13:13 Alan Mackenzie <acm@muc.de> wrote:

> Hello, Wol.
>
> On Mon, Apr 05, 2021 at 18:44:15 +0100, antlists wrote:
> > On 05/04/2021 18:12, Alan Mackenzie wrote:
> > > Bug reports and other comments are welcome, of course.
> > >
> > > If anybody would like the corresponding patch which works on 5.4.n,
> for n
> > >> = 80, that is available, too.
>
> > Why did it get removed from the kernel?
>
> Allegedly, there were security problems with it.  I think the kernel
> people had a program which fired random inputs at lots of components,
> and noted when things went wrong; and things went wrong in the scroll
> back component.  And they couldn't find anybody to look into these
> problems.
>
> That's the official position.  I'm a bit more cynical about it.
>
> > If you want to get it back in, couldn't you ping Greg KH and get some
> > help - or even just advice - getting it accepted?
>
> I have no reason to believe all the "security problems" will have been
> resolved by my hacking.  I took the algorithmic bits from 4.19.97
> basically unchanged.
>
> Maybe there's not much enthusiasm for this feature, in which case I will
> keep it working for myself.  Linux is basically unusable to me without
> it.  There are probably quite a few patches to restore the scrollback
> floating around the web by now: the changes were not particularly
> difficult to anybody who knows the code, but getting to know the code
> was unusually difficult.
>
> We'll see how people react to it here, first.
>
> > Cheers,
> > Wol
>
> --
> Alan Mackenzie (Nuremberg, Germany).


Without looking at the patch itself:

Have you considered something like kmscon as a userland alternative?

I installed it on my laptop, and aside from not working with gpmd or
consolation for mouse support, it's a perfectly functional local tty.