Re:Re: matroxfb problems with dualhead G400

Re:Re: matroxfb problems with dualhead G400

[Petr Vandrovec]

On  3 Sep 01 at 15:15, Ghozlane Toumi wrote:
> > You must boot your kernel with 'video=scrollback:0'. Otherwise your
> > kernel die sooner or later... JJ's scrollback code does not cope with
> > more than one visible console, so you must disable it if you have more
> > than one display in the box.

> could we somehow detect in register_framebuffer that whe're going
> multihead and disable software scrolling ?
> 
> I didn't look at the code so i don't know if it's feasible , just a
> suggestion ..

Unfortunately once scrollback gets enabled (and allocates its scrollback
buffers, fills couple of pointers here and there), it is not trivial to 
disable it again. If someone feels for doing that, do that. But I think
that changing default scrollback value from 32768 to 0 is better - as
you'll still have scrollback if your hardware can do it.
                                            Best regards,
                                                Petr Vandrovec
                                                vandrove@vc.cvut.cz
                                                
                                    
                                            

Re:Re: matroxfb problems with dualhead G400

[James Simmons]

> > could we somehow detect in register_framebuffer that whe're going
> > multihead and disable software scrolling ?
> > 
> > I didn't look at the code so i don't know if it's feasible , just a
> > suggestion ..
> 
> Unfortunately once scrollback gets enabled (and allocates its scrollback
> buffers, fills couple of pointers here and there), it is not trivial to 
> disable it again. If someone feels for doing that, do that. But I think
> that changing default scrollback value from 32768 to 0 is better - as
> you'll still have scrollback if your hardware can do it.

I agree for 2.4 kernels the solution Petr stated is the best. It is not
easy to properly implement soft scrollback. Sometime ago I worked on a new
scrollback implementation that was more in the upper console layers so
other systems could take advanatge of it. It is not a easy problem to
solve. In the next following weeks I should start working on this again.

Re:Re: matroxfb problems with dualhead G400

[Ghozlane Toumi]

Monday, September 03, 2001 4:51 PM, You wwrote:
> On  3 Sep 01 at 0:25, Benjamin Gilbert wrote:
> > [ software scroll back kills on dualhead ]
>
> You must boot your kernel with 'video=scrollback:0'. Otherwise your
> kernel die sooner or later... JJ's scrollback code does not cope with
> more than one visible console, so you must disable it if you have more
> than one display in the box.
>                                                 Petr Vandrovec

could we somehow detect in register_framebuffer that whe're going
multihead and disable software scrolling ?

I didn't look at the code so i don't know if it's feasible , just a
suggestion ..

ghoz