Re: [Intel-gfx] [PATCH 03/21] fbcon: Restore fbcon scrolling acceleration

Daniel Vetter
2022-02-01T10:37:01Z

On Tue, Feb 1, 2022 at 11:16 AM Helge Deller <deller@gmx.de> wrote:
>
> On 1/31/22 22:05, Daniel Vetter wrote:
> > This functionally undoes 39aead8373b3 ("fbcon: Disable accelerated
> > scrolling"), but behind the FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION
> > option.
>
> you have two trivial copy-n-paste errors in this patch which still prevent the
> console acceleration.

Duh :-(

But before we dig into details I think the big picture would be
better. I honestly don't like the #ifdef pile here that much. I wonder
whether your approach, also with GETVX/YRES adjusted somehow, wouldn't
look cleaner? Like I said in the cover letter I got mostly distracted
with fbcon locking last week, not really with this one here at all, so
maybe going with your 4 (or 2 if we squash them like I did here)
patches is neater?

Cheers, Daniel

>
> > diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
> > index 2ff90061c7f3..39dc18a5de86 100644
> > --- a/drivers/video/fbdev/core/fbcon.c
> > +++ b/drivers/video/fbdev/core/fbcon.c
> > @@ -1125,13 +1125,15 @@ static void fbcon_init(struct vc_data *vc, int init)
> >
> > ops->graphics = 0;
> >
> > - /*
> > - * No more hw acceleration for fbcon.
> > - *
> > - * FIXME: Garbage collect all the now dead code after sufficient time
> > - * has passed.
> > - */
> > +#ifdef CONFIG_FRAMEBUFFER_CONSOLE_ROTATION
>
> should be:
> #ifdef CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION
>
>
> > + if ((info->flags & FBINFO_HWACCEL_COPYAREA) &&
> > + !(info->flags & FBINFO_HWACCEL_DISABLED))
> > + p->scrollmode = SCROLL_MOVE;
> > + else /* default to something safe */
> > + p->scrollmode = SCROLL_REDRAW;
> > +#else
> > p->scrollmode = SCROLL_REDRAW;
> > +#endif
> >
> > /*
> > * ++guenther: console.c:vc_allocate() relies on initializing
> > @@ -1971,15 +1973,49 @@ static void updatescrollmode(struct fbcon_display *p,
> > {
> > struct fbcon_ops *ops = info->fbcon_par;
> > int fh = vc->vc_font.height;
> > + int cap = info->flags;
> > + u16 t = 0;
> > + int ypan = FBCON_SWAP(ops->rotate, info->fix.ypanstep,
> > + info->fix.xpanstep);
> > + int ywrap = FBCON_SWAP(ops->rotate, info->fix.ywrapstep, t);
> > int yres = FBCON_SWAP(ops->rotate, info->var.yres, info->var.xres);
> > int vyres = FBCON_SWAP(ops->rotate, info->var.yres_virtual,
> > info->var.xres_virtual);
> > + int good_pan = (cap & FBINFO_HWACCEL_YPAN) &&
> > + divides(ypan, vc->vc_font.height) && vyres > yres;
> > + int good_wrap = (cap & FBINFO_HWACCEL_YWRAP) &&
> > + divides(ywrap, vc->vc_font.height) &&
> > + divides(vc->vc_font.height, vyres) &&
> > + divides(vc->vc_font.height, yres);
> > + int reading_fast = cap & FBINFO_READS_FAST;
> > + int fast_copyarea = (cap & FBINFO_HWACCEL_COPYAREA) &&
> > + !(cap & FBINFO_HWACCEL_DISABLED);
> > + int fast_imageblit = (cap & FBINFO_HWACCEL_IMAGEBLIT) &&
> > + !(cap & FBINFO_HWACCEL_DISABLED);
> >
> > p->vrows = vyres/fh;
> > if (yres > (fh * (vc->vc_rows + 1)))
> > p->vrows -= (yres - (fh * vc->vc_rows)) / fh;
> > if ((yres % fh) && (vyres % fh < yres % fh))
> > p->vrows--;
> > +
> > + if (good_wrap || good_pan) {
> > + if (reading_fast || fast_copyarea)
> > + p->scrollmode = good_wrap ?
> > + SCROLL_WRAP_MOVE : SCROLL_PAN_MOVE;
> > + else
> > + p->scrollmode = good_wrap ? SCROLL_REDRAW :
> > + SCROLL_PAN_REDRAW;
> > + } else {
> > + if (reading_fast || (fast_copyarea && !fast_imageblit))
> > + p->scrollmode = SCROLL_MOVE;
> > + else
> > + p->scrollmode = SCROLL_REDRAW;
> > + }
> > +
> > +#ifndef CONFIG_FRAMEBUFFER_CONSOLE_ROTATION
>
> same here... it needs to be:
> #ifdef CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION
>
>
> > + p->scrollmode = SCROLL_REDRAW;
> > +#endif
> > }
> >
> > #define PITCH(w) (((w) + 7) >> 3)
> >
>
> still reviewing the other patches...
>
> Helge

--
Daniel Vetter
Software Engineer, Intel Corporation