From owner-freebsd-current  Wed Jan  5 23:44:49 2000
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From: Soren Schmidt <sos@freebsd.dk>
Message-Id: <200001060743.IAA71954@freebsd.dk>
Subject: Re: Mounting CD-ROM with ATA driver hangs system
In-Reply-To: <00Jan6.151359est.40327@border.alcanet.com.au> from Peter Jeremy at "Jan 6, 2000 03:13:59 pm"
To: peter.jeremy@alcatel.com.au (Peter Jeremy)
Date: Thu, 6 Jan 2000 08:43:35 +0100 (CET)
Cc: freebsd-current@FreeBSD.ORG
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It seems Peter Jeremy wrote:
> I just discovered that my ATAPI CD-ROM is no longer usable - when I
> try to mount it, my maching hangs (hard).
> 
> I'm running -current from cvs-cur 5961 (Monday about 0000UTC).
> 
> The symptoms are:
> 
> Run "mount -r /dev/acd0c /cdrom"
> The CD-ROM activity light flashes briefly and the CD-ROM spins up.
> The activity light then goes hard on for something like 20 seconds.
> The kernel then prints:
> 	acd0: atapi_timeout: cmd=READ_BIG - resetting
> 	ata0: resetting devices .. _
> The cursor remains at the end of the line ("_" above).  The CD-ROM
> spins up and down.  The HDD light stays hard on.

> acd0: <CD-ROM CDU611/2.0a> CDROM drive at ata0 as slave 
> acd0: read 1723KB/s (1723KB/s), 256KB buffer, DMA
                                                ^^^
You have enabled ATAPI DMA in your kernel config, dont, your
drive apparently doesn't support it.
DMA on ATAPI devices is disabled as default because _lots_ and I mean
_lots_ of ATAPI devices claim to do DMA, but they actually dont :(

-Søren


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