[haiku-development] Re: Anyone seen this - Vesa delay
- From: Stephan Assmus <superstippi@xxxxxx>
- To: haiku-development@xxxxxxxxxxxxx
- Date: Thu, 10 Jul 2008 08:37:38 +0200
Jan Klötzke wrote:
> Bruno Albuquerque <bga@xxxxxxxxxxxxx> wrote:
> > Jan Klötzke escreveu:
> > > Bruno Albuquerque <bga@xxxxxxxxxxxxx> wrote:
> > >> KERN: vm_soft_fault: va 0x10ffc not covered by area in address space
> > >> KERN: vm_page_fault: vm_soft_fault returned error 'Bad address' on
> > >> fault at 0x10ffc, ip 0x4cab, write 1, user 1, thread 0xed KERN:
> > >> vm_page_fault: sending team "app_server" 0x60 SIGSEGV, ip 0x4cab
> > >> ("???" +0x4cab)
> > >> KERN: vesa: vbe_get_mode_info(326): vm86 failed
> > >> KERN: vesa: vesa_set_display_mode(): cannot get mode info
> > >
> > > This looks like something else. I don't know why but the BIOS code
> > > seems to touch an address which it shouldn't access. Maybe another
> > > error in the emulation part but you could also change the following
> > > line in src/add-ons/kernel/drivers/graphics/vesa/vesa.cpp from:
> > > status_t status = vm86_prepare(&vmState, 0x2000);
> > > to...
> > > status_t status = vm86_prepare(&vmState, 0x20000);
> > > .
> > >
> > > This will cover the location where the page fault happened. Maybe it
> > > helps for the time being...
> >
> > Yep, this worked like a charm. Ut booted straight to the highest
> > supported VESA mode in my monitor (1400x1050) and I was able to change
> > resolutions on the fly. What are the drawbacks of this change?
>
> Well, the change itself has no drawback but the root cause remains
> unknown which gives me a bit of a headache. The VESA BIOS should not
> access address
> 0x10ffc. And that it's a write access makes it even more suspicious.
>
> I did not have the time yet to look into this more deeply. OTOH applying
> the change doesn't harm and apparently improves things...
>
> BTW: Stephan, does it also help in your case?
Yes, I can switch resolutions on the fly now.
I am observing though that graphics speed has degraded. I will temporarily
revert the change and check if that was the cause. Will let you know. Maybe
something goes wrong with the write combining when the resolution switch
actually succeeds? Could be another change though that caused it.
Best regards,
-Stephan
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