[alsa-devel] [PATCH] opti931: additional check for OPL3 device

Clemens Ladisch cladisch at fastmail.net
Mon Sep 17 12:39:53 CEST 2007

Rene Herman wrote:
> On 09/17/2007 10:14 AM, Clemens Ladisch wrote:
> > Krzysztof Helt wrote:
> >> Should the OPL4 detection has the same fallback or just all Opti cards
> >> should search the FM chip at the range + 8 address?
> > 
> > It appears a fallback shoudn't be needed because the chip always returns 
> > a range suitable for an OPL4.
> > 
> > Since an OPL3 range is never larger than 8 bytes, and OPL4 needs 16 
> > bytes, we could add 8 to get the FM address _if_ the range is at least 16
> > bytes; thus we are safe even if a chip publishes an OPL3-only range.
> At least 16 won't do -- the OPTi chip provides a 12-byte range. More than 8 
> would work, but just +8 is fine. I have all OPTi ISA-PnP chips (924, 925, 
> 931, 933) and more aren't going to be produced. The 0x380 base is what it 
> calls the OPL4Base and ALBase (AdLib) is at 0x388.

Are there chips that have both OPL4Base and ALBase?

> The chip can defer to external FM it seems, but even if there are OPTi/OPL4 
> combo's out there in the wild (I sort of doubt it)


> the driver's just doing opl3 anyway. ie, still needs just the +8.

Only the 93x driver; the 92x driver has OPL4 support.


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