umass/cam headaches

Ulrich Spoerlein uspoerlein at
Fri Jul 6 16:43:23 UTC 2007

On Thu, 05.07.2007 at 21:14:31 -0600, M. Warner Losh wrote:
> In message: <20070705184309.GD2749 at roadrunner.q.local>
>             Ulrich Spoerlein <uspoerlein at> writes:
> : I'm still fighting with getting my ext. Plextor drive to read retail
> : DVDs and noticed these new printfs. I don't know *what* has been done to
> : CAM or cd(4) or umass(4) during the last week. But my drive is working
> : way better than before.
> I'm unsure what I've done, but you are welcome.

I've spoken too soon. I did not change the configuration in any way, but
after rebooting am at square one again.

> : Then what about 0x46 and 0x4a? Could they be the source of my problem?
> : What's with the SCSI status errors? Is READ(10) telling me it's using 10
> : byte commands? The CDB is 10 bytes.
> I'm afraid I don't know your problem.  What kind of retail DVDs are
> you reading?  Movies?

Any kind of retail (== non-self burned) DVDs, be they video DVDs or data
DVDs as you find frequently with PC magazines.

It's not that I can get mplayer/xine working, it's that the drive
refuses even the most basic ioctl once such a media is inserted. Just
like non is inserted at all. Yet the driver somehow groks it, at least
upon device detection

umass0: <PLEXTOR DVDR   PX-755A, class 0/0, rev 2.00/4.35, addr 8> on uhub3
cd0 at umass-sim0 bus 0 target 0 lun 0
cd0: <PLEXTOR DVDR   PX-755A 1.06> Removable CD-ROM SCSI-0 device 
cd0: 40.000MB/s transfers
cd0: cd present [4169920 x 2048 byte records]

So, its telling me the size of the disk, but then
# diskinfo -v /dev/cd0
diskinfo: /dev/cd0: ioctl(DIOCGMEDIASIZE) failed, probably not a disk.: No such file or directory
Exit 1

Neither cat(1), dd(1), or any other tool can do something about it.

When I wrote my last mail, I did change the media several times and
besides some noise error messages they would mostly work (hey, glabel
found the disk label, what more can I expect!).

Are there good OpenBSD or NetBSD Live CDs out there? I already confirmed
that the drive is working fine under Windows and Linux, so testing under
other BSDs would be the next step.

Ulrich Spoerlein
"The trouble with the dictionary is you have to know how the word is
spelled before you can look it up to see how it is spelled."
-- Will Cuppy

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