Strange problem with Panasonic DVD RW drive

Ion-Mihai Tetcu itetcu at
Thu Feb 23 04:32:49 PST 2006

On Thu, 23 Feb 2006 20:15:31 +0800
Geoff Glasson <g_glasson at> wrote:

> Hi,
> I'm having a really strange problem with my DVD drive in my Athlon64
> X2 box, in that I'm unable to mount a CDROM because the machine
> thinks there is a hardware error.  The strange thing is, that this
> failure is dependent upon the mode in which I boot the machine.  
> For example, if I boot my machine with the CD in the drive, the
> machine reads the disc and boots quite happily from the CD.  If I
> boot the machine without the CD into safe mode, I'm able to manually
> mount the CD and read it, however if I boot my machine normally I
> cannot mount the CD and mount reports the following error
> "mount_cd9660: /dev/acd0: Input/output error".  
> dmesg reports :
> "Trying to mount root from ufs:/dev/ad12s1a
> acd0: FAILURE - READ_BIG HARDWARE ERROR asc=0x08 ascq=0x03 error=0
> g_vfs_done():acd0[READ(offset=32768, length=2048)]error = 5"
> In all cases, the same FreeBSD AMD RC1 boot disc is used, so I know
> the disc is OK.
> Has anyone else seen this type of problem?  Any ideas how to resolve
> it?  Is there any difference between the default boot mode and safe
> mode that is likely to cause this problem?

In safe mode you have hw.ata.atapi_dma=0. Try setting it to 0 at loader
prompt and boot -v and see if you can mount the CD. Try changing the
cable anyway.

What MB/chip-set ?

IOnut - Unregistered ;) FreeBSD "user"
  "Intellectual Property" is   nowhere near as valuable   as "Intellect"

Ferengi Rule of Acquisition #189:
	Let others keep their reputation. You keep their latinum.
		-- ST: Legends of the Ferengi

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