Karl Fischer wrote:
>
> nope nope wrote:
> >
> > Normally I'd go straight to the writer of the driver with this problem but
> > he's anonymous, soo...
> > I've been getting the same hard freezes as a lot of people who are trying to
> > use Neomagic nm256 audio. What's causing the lockups, at least on my Dell
> > Latitude LS, is the ac97_codec driver trying to read (not write) a few
> > standard AC97 registers. In particular anytime the AC97_RESET register
> > (defined in ac97.h as 0x00) is accessed the machine instantly crashes. This
> > also occurs for several other registers. Does anyone have any idea why this
> > might be occuring? It's not like the driver is trying to _write_ to any
> > memory - at least then the crashes would make a little bit of sense. Just
> > reading those registers kills it. The Windows drivers for this chip work
> > fine; I wish I knew a bit more about how to delve into the interals of
> > Windows so I could see just how that driver finesses the AC97 registers
> > without locking the machine. Is anyone aware of any sort of conflict that
> > I'm missing here? Advice on how to proceed? Thanks!
>
> I'm new to this list and don't know too much about driver programming,
> but I had similar problems writing some assembly programs years ago.
>
> My problems were mainly caused by doing 16-bit access to 8-bit registers.
> The CPU-/Chipset does some automatic serialisation of those requests, but
> sometimes the timing is critical. For my problems it helped to split the
> requests into 8-bit io's with some NOP's in between ...
the problem here is more an overlap problem, the nm256 chipset is used for
both display and sound and uses 2.5MB of ram, a few KB at the end are
reserved for the sound, on my vaio it works well, but, the end of the video
may not be clearly defined on the latitude.
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This archive was generated by hypermail 2b29 : Mon Jul 31 2000 - 21:00:22 EST