[hatari-devel] Hatari interrupts still assert, if VDI mode is used

Eero Tamminen eerot at users.berlios.de
Sun Aug 9 22:43:45 CEST 2009


Hi,

On Sunday 09 August 2009, npomarede at corp.free.fr wrote:
> On Sun, 9 Aug 2009, Eero Tamminen wrote:
> >> Latest Hatari version in repo still asserts.  It happens always on
> >> startup if I do following:
> >> ./hatari --machine tt --tos etos512k.img -s 14 --vdi-planes 1
> >> --vdi-width 800 --vdi-height 600  -d .
> >
> > Happens also when starting with ST, STE or Falcon emulation if VDI
> > resolution is used.
>
> Good catch, it's true I don't really use this mode and forgot to test it.
>
> Some tests were required to not change HBL / Timer B interrupt when
> frequency is changed.
> Fix committed, no more crash for me.
>
> By the way, is frequency change between 50/60 Hz really possible ? I
> don't think we need to handle this, so I could add in
> Video_Sync_WriteByte :
>
>  	if (bUseVDIRes)
>  		return;
>
> Does it looks reasonable ?

VDI mode doesn't need / shouldn't need to support:
- monitor frequency switching
- run-time resolution switching
- palette switching / spec-512
- borders

I actually tried earlier to use VDI modes with a very low frequency to
minimize the overhead from the video interrupts (when using e.g.
fast-forward with GEM applications), but that was interfering with the rest
of the emulation: sound, display update speed etc. so I dropped it.

Summary: please use a fixed frequency that gives least amount of interrupts
but still keeps Hatari working fine.


	- Eero



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