Re: 2.6.9-rc1: scrolling with tdfxfb 5 times slower

Paolo Ornati
2004-09-01T11:54:44Z

On Wednesday 01 September 2004 12:51, Antonino A. Daplas wrote:
> On Wednesday 01 September 2004 18:21, Antonino A. Daplas wrote:
> > On Wednesday 01 September 2004 15:20, Paolo Ornati wrote:
> > > Ok, with this patch and CONFIG_FB_3DFX_ACCEL=y the scrolling speed
> > > comes back (only a bit slower than with 2.6.8.1 without
> > > CONFIG_FB_3DFX_ACCEL):
> > >
> > > $ time cat MAINTAINERS: ~2.67s
> >
> > Ok. However, I'm still wondering at the scrolling speed, it's a bit
> > slower than what I would expect (I get < 1 second with vesafb which is
> > completely unaccelerated).
>
> Ok, I think I know why the scrolling speed is too slow, the driver is not
> maximizing the extra memory of the framebuffer.
>
> This patch sets info->var.yres_virtual to the maximum upon driver load.
> If this works, it's possible to get sub-1 second scrolling speed.
>
> Reverse the previous patch first, then apply this patch.

Results for 2.6.9-rc1 + your patch (time cat MAINTAINERS):

CONFIG_FB_3DFX_ACCEL=n
~1.27 s

CONFIG_FB_3DFX_ACCEL=y
~0.18 s

BUT with CONFIG_FB_3DFX_ACCEL enabled I get strange video
"corruptions" (like bitmaps with random colors) that go away simply
swithcing to another console and than back to the previous.

--
Paolo Ornati
Gentoo Linux (kernel 2.6.9-rc1)