[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: XF4 on Mach64 and 2.2 kernel?



Sven LUTHER wrote:

> > > I don't know shadowfb enough to know how it works, but i guess you write
> > > to the shadowfb, which in turn get copied to the true screen every now
> > > and then.
> >
> > Yes. The ShadowFB we are talking about does the copy after each operation.
> > Keith Packard wrote another shadow framebuffer implementation for Tiny X
> > which only does it in regular intervals which should further improve
> > performance at the cost of latency, don't know if it will (or even can) be
> > integrated into the 'normal' XFree86 server.
> 
> mmm, ...
> 
> don't know if this would really help here, especially if you want to retain
> the visual aspect of it.

What do you mean? AFAIK Keith's code refreshes the display 50 times a second,
maybe it could even be done during vertical retrace at least on some hardware.


> > GNOME draws stippled rectangles, which leads to the whole area of the
> > rectangles being copied from the shadow framebuffer to the real one. If it
> > drew the rectangles using four lines instead, it should be much faster.
> 
> Or if we have some magic in shadowfb that know whatdid change and what not,
> but i think this would be expensive, well not in bus cycle, but in memory
> accesses.
> 
> So no real way out of this, maybe we should fill a bug against gnome ?

Not a bad idea. AFAIR there was a discussion about this on one of the X
mailing lists with a GNOME developer so I assumed it had already been fixed.


Michel


-- 
Earthling Michel Dänzer (MrCooper)  \  CS student and free software enthusiast
Debian GNU/Linux (powerpc,i386) user \   member of XFree86 and the DRI project



Reply to: