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Date:      Mon, 12 Jan 98 19:58:20 EST
From:      luoqi@watermarkgroup.com (Luoqi Chen)
To:        freebsd-current@FreeBSD.ORG, freebsd-multimedia@FreeBSD.ORG, scottm@cs.ucla.edu
Subject:   Re:  NEC 273 CD-ROM
Message-ID:  <9801130058.AA24177@watermarkgroup.com>

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Scott Michel wrote:
> This is an ATAPI critter, but for some reason at bootstrap, there's
> an out of phase error. Suggestions on how to debug it? (This should
> mean: I'm willing to debug it, I'm willing to fix and patch the
> driver, but how to I go about debugging?)
I have the same drive and the same problem. The problem is that during
bootstrap, interrupt is not used, instead, interrupt reason & status
registers are polled to determine the phase. Because two registers are
involved, chances are you may be reading when value of one reg. has
changed and the other has not, and the driver reports an unknown phase error.
I tried to fix it with unsatifactory results. Eventually I gave up,
it wouldn't affect anything after the system is up.

If you want to give it a try, look at function atapi_request_immediate().
You need to figure out when both ireason & status registers are stablized
and would give a correct phase reading.
> 
> 
> -scooter
> -- 
> Scott Michel                        | In life, there are sheep and there are
> UCLA Computer Science		    | wolves.
> PhD Graduate Student                |           I don't bleat.
> 
-lq



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