Messages in this thread |  | | | Date | Wed, 26 Jul 2000 00:42:00 +0200 | | From | Karl Fischer <> | | Subject | Re: Found cause of NM256 freezes |
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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 ...
HTH
Karl
"... sometimes you get answers to questions you never asked ..."
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