Re: [PATCH v2 0/4] have the vt console preserve unicode characters

[Nicolas Pitre]

On Fri, 22 Jun 2018, Alan Cox wrote:

> > The other point is a quite pointless assumption that existing scrollback is
> > "optimized".  Even vgacon mostly uses software scrollback these days, as the
> > amount of VGA display memory is really small.
> 
> All of our console driver code is horribly unoptimized for most of
> todays hardware. Long ago I did look at what was needed but it's a
> seriously non-trivial change. In particular
> 
> - Console I/O occurs under enough locks to keep fort knox safe. That
>   means it's very very hard to accelerate
> 
> - The logic is plain wrong for a lot of modern video. We shouldn't be
>   scrolling, we should be rendering the current backing text buffer at
>   video refresh rate or similar and if the source of the updates outruns
>   us it doesn't matter - we don't have to draw all the glyphs as if we
>   were fast enough they would have been a blur anyway.

My executive summary from what you say is that there is no longer an 
advantage to maintain a central vga-style glyph buffer in the core 
console code, right?


Nicolas