Re: tdfx framebuffer garbles display in 2.6.19.5

["Antonino A. Daplas" <adaplas@gmail.com>]

On Mon, 2007-02-26 at 18:13 +0100, DervishD wrote:
>     Hi Antonino :)
> 
>  * Antonino A. Daplas <adaplas@gmail.com> dixit:
> > On Mon, 2007-02-26 at 15:47 +0100, DervishD wrote:
> > >     From time to time, the tdfxfb driver from 2.6.19.5 (sorry, I cannot
> > > test in 2.6.20.x because it doesn't compile, the infamous BDF negative
> > > offset problem) garbles the display, leaving only a lot of thin lines,
> > > just like sync was lost. The display can be repaired by switching to
> > > another console, but this is annoying. This happens with a Voodoo 3
> > > 3000, using 800x600x8@100 mode.
> > 
> > Try fbset -a -vyres 600 first and let us know of the result.
> 
>     After doing this, I no longer can garble the display (before, just a
> "ls -lR /" was enough to do it, in fact, any big output garbled the
> display). The only problem with this solution is that the scroll speed
> has decreased a bit. In fact, the scroll speed is affected by the vyres
> parameter a lot! The highter the vyres, the faster the scroll, and I
> cannot reproduce the problem anymore after changing it once!

Display panning is what makes scrolling fast which is the default scroll
method if vyres > yres.  Unfortunately, tdfxfb occasionally have
problems with this method, the higher the vyres, the greater the
likelihood of screen corruption. That's why tdfxb limits the vyres to a
maximum of 4096. As to why the problem disappeared just by changing this
parameter, that I too don't know.

Tony