FreeBSD doesn't find my CD-RW and sometimes my DVD
Andrew P. Lentvorski, Jr.
bsder at allcaps.org
Fri Jul 25 15:52:37 PDT 2003
On Fri, 25 Jul 2003, Lia Maggioni wrote:
> ACD0 is only the DVD , CD-RW (a Liteon 52x 24x 52x) isn't found at all!!
> Literally from DMESG:
> ata0-slave: ATA identify retries excedeed
> and sometimes it doesn't find my DVD too , with the message :
> ata1-slave: ATA identify retries excedeed
I would recommend setting the jumpers rather than using the cable select;
it simply removes one variable from the problem.
Take the CD off of the same cable as your hard drive. I would probably
replace the DVD with the CD-RW to see if that works. Then I would
probably try to put the DVD and CD-RW on the same cable.
Check that your ATA cable doesn't violate the ATA specs (I think that 18"
is the limit for an "in-spec" ATA cable. Yes, that's *short*.)
I have been seeing this kind of intermittent problem with the ATA
subsystem since the ATA rewrite. It has persisted into 5.1 Release. To be
fair, the failures are intermittent (read: really hard to debug), and I
haven't checked any of the old FreeBSD releases; so I am reluctant to
complain too loudly.
It seems that heterogeneous combinations of devices on the same cable give
FreeBSD problems. ie. a UDMA 100 and a PIO 4 device on the same cable.
Normally this shows up as the slower device not being detected. Putting
slow devices on their own cable seems to cut down on the probability.
I presume that the issue is something along the lines of the chipsets in
the slow device are slightly out of spec and the FreeBSD driver refusing
to coddle broken hardware. I am hesitant to blame FreeBSD as this may
simply be a case of FreeBSD reporting the failure while other OS's simply
degrade badly and hide the problem.
However, it is annoying as it's a complete crapshoot as to whether my ATA
CD-RW will be found on any given day. I've tried 4 different
motherboards, 6 different types of cables, and 4 different CD-RW's. All
of them exhibit some intermittent failures.
I'm really looking forward to Serial ATA. Point to point connection
should eliminate whole classes of this kind of breakage.
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