Re: [hatari-devel] Hatari hangs with NVDI when MMU is enabled

[Uwe Seimet <Uwe.Seimet@xxxxxxxxx>]

Hi,

> I reproduced the issue seen by christian, after some debugging / 
> tracing, the problem is that cache state was not consistent in the case 
> of 68030 + mmu with more_compatible=off and cycle_exact=off.
> Some functions were accessing memory through the data cache, other were 
> not, so in the end the value written to change trap's vector was not 
> seen by the exception handler :(
> 
> After discussing with Toni, this options' combination is in fact not 
> valid : data cache emulation requires either more_compatible or 
> cycle_exact, so if none are set, data cache emulation should be disabled
> 
> The problem would the same with 68030 and no mmu, but in that case the 
> code path is different and data cache is not used by cpu emulation even 
> if it was enabled, which explain why there was no crash.
> 
> Change was committed to disable cache when necesary, with or without MMU.
> 
> Please, test if NVDI works better now.

I'm afraid there is no change. When I switch on PMMU support only (no
prefetch, no cycyle exact) NVDI still hangs. Maybe I misunderstand what
you wrote above, but just PMMU only should work now, shouldn't it?

I have to admit, I do not understand why these options are not
independent, and why enabling the PMMU and *either* cycle exact *or*
prefetch changes the behavior. This sounds like an intransparent
side-effect to me

Best regards

Uwe