On Aug 7, Bill Studenmund wrote
> I'm looking into porting FreeBSD's CMD640 support. Basically it gets
> around the chip's buggyness by not using DMA (we already have that :-) and
> by keeping one command queue for both the secondary and primary IDE
> channels on the chip.
> 
> Well, I'm having a bit of difficulty understanding exactly what we're
> doing. I've stared at the code for a bit, and am wondering if someone more
> familiar with the wd system could give suggestions.

I think you should start from the driver from the scsipi branch (which
should be merged in the trunk as soon as someone from core says 'ok').
The wdc driver here has a per device and per controller queue, which 
should ease the implementation of the workaround (basically, you need
to consider it is not two separate controllers but only one, and thus
send only one command at a time).

I have in project to rewrite the wd/wdc driver, in order to get it more
MI and support pci chipsets (and thus DMA and workarounds for buggy
chips). But I will not start this before september.

I can make the scsipi sources available from FTP if you need.

--
Manuel Bouyer, LIP6, Universite Paris VI.           Manuel.Bouyer@lip6.fr
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