Upgrade 2.6.12-rc4 -> 2.6.13.1 broke DVD-R writing (fails consistenly in OPC phase)

[Ville Herva <v@iki.fi>]

After I upgraded from 2.6.12-rc4 to 2.6.13.1, I can no longer write DVD-R
(haven't tried DVD+R nor CD-R). 

The command 

 growisofs -r -l -J -R -f -graft-points ${=FILES} -Z /dev/hdc

always gives:

 :-[ PERFORM OPC failed with SK=3h/ASC=73h/ACQ=03h]: Input/output error

Nothing relevant in dmesg.

The drive is Optoride DVD±RW DD0401, the medium is Verbatim DVD-R 8x, and
the chipset is i815; Celeron Tualatin 1.4GHZ; Abit ST6R.

I tried the growisofs command probably a dozen times, rebooted and powered
off in the middle¹. I tried a couple of other discs from the same ("known
good") batch. cdrecord also fails. I tried to set -speed=1, 2, 4, but
growisofs claims setting speed to anything but 8x does not succeed.

The drive is able to read CD and DVD media just fine with 2.6.13.1.

I booted back to 2.6.12-rc4 and the recording succeeded at the first try. I
used the exact same disc that had failed with 2.6.13.1.

The .config from 2.6.12-rc4 and 2.6.13.1 is nearly identical, but with
2.6.13.1 I use HZ=250 (that being the default nowadays) and 
2.6.13.1 has CONFIG_PREEMPT_VOLUNTARY=y instead of 2.6.12-rc4's
CONFIG_PREEMPT=y and CONFIG_PREEMPT_BKL=y ².

Any ideas?


-- v -- 

v@iki.fi

¹) In past, the DVD-R drive has sometimes gotten so confused it needs a
   power off before it co-operates. However, in those cases it has stopped 
   responsing altogether, which it didn't do this time.
²) The desktop does seem more responsive with 2.6.13.1-