[Nouveau] [PATCH] fbcon: Disable accelerated scrolling

Jiri Slaby
Thu, 29 Oct 2020 05:42:39 -0000

On 28. 10. 20, 17:06, Daniel Vetter wrote:
> So ever since syzbot discovered fbcon, we have solid proof that it's
> full of bugs. And often the solution is to just delete code and remove
> features, e.g.  50145474f6ef ("fbcon: remove soft scrollback
code").
...
> --- a/drivers/video/fbdev/core/fbcon.c
> +++ b/drivers/video/fbdev/core/fbcon.c
> @@ -1147,11 +1147,13 @@ static void fbcon_init(struct vc_data *vc, int
init)
>
>   	ops->graphics = 0;
>
> -	if ((cap & FBINFO_HWACCEL_COPYAREA) &&
> -	    !(cap & FBINFO_HWACCEL_DISABLED))
> -		p->scrollmode = SCROLL_MOVE;
> -	else /* default to something safe */
> -		p->scrollmode = SCROLL_REDRAW;
> +	/*
> +	 * No more hw acceleration for fbcon.
> +	 *
> +	 * FIXME: Garabge collect all the now dead code after sufficient time

If you go this non-invasive path, then only a nit here: "Garbage"

thanks,
--
js
suse labs