With current rawhide, I can't burn to a DVD-RW with growisofs.  Here's what it prints:

Executing 'mkisofs -dvd-video /tmp/dvdburn.4393/dvd | builtin_dd of=/dev/dvdrw obs=32k seek=0'
I: -input-charset not specified, using iso-8859-1 (detected in locale settings)
  0.43% done, estimate finish Sat Sep 20 23:15:28 2008
/dev/dvdrw: engaging DVD-RW DAO upon user request...
/dev/dvdrw: reserving 1163209 blocks
/dev/dvdrw: "Current Write Speed" is 4.1x1352KBps.
  0.86% done, estimate finish Sun Sep 21 00:07:48 2008
:-[ WRITE@LBA=bf0h failed with SK=2h/LOGICAL UNIT IS IN PROCESS OF BECOMING READY]: Resource temporarily unavailable
:-( write failed: Resource temporarily unavailable
/dev/dvdrw: flushing cache
:-[ FLUSH CACHE failed with SK=2h/LOGICAL UNIT IS IN PROCESS OF BECOMING READY]: Resource temporarily unavailable

And here's what the kernel logs:

Sep 20 23:16:56 jik2 kernel: ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
Sep 20 23:16:56 jik2 kernel: ata2.00: cmd a0/01:00:00:20:00/00:00:00:00:00/a0 tag 0 dma 16416 in
Sep 20 23:16:56 jik2 kernel:         cdb 51 00 00 00 00 00 00 00  20 00 00 00 00 00 00 00
Sep 20 23:16:56 jik2 kernel:         res 40/00:03:00:0c:00/00:00:00:00:00/a0 Emask 0x4 (timeout)
Sep 20 23:16:56 jik2 kernel: ata2.00: status: { DRDY }
Sep 20 23:17:01 jik2 kernel: ata2: link is slow to respond, please be patient (ready=0)
Sep 20 23:17:06 jik2 kernel: ata2: device not ready (errno=-16), forcing hardreset
Sep 20 23:17:06 jik2 kernel: ata2: soft resetting link
Sep 20 23:17:08 jik2 kernel: ata2.00: configured for UDMA/66
Sep 20 23:17:08 jik2 kernel: ata2: EH complete
Sep 20 23:17:14 jik2 kernel: end_request: I/O error, dev sr0, sector 0
Sep 20 23:17:14 jik2 kernel: Buffer I/O error on device sr0, logical block 0
Sep 20 23:17:14 jik2 kernel: end_request: I/O error, dev sr0, sector 0
Sep 20 23:17:14 jik2 kernel: Buffer I/O error on device sr0, logical block 0

This problem does not occur with a DVD+R.

I've tried downgrading to kernel-2.6.26.3-29.fc9.i686 and kernel-2.6.25-14.fc9.i686, and neither of them solved this problem.  (This suggests that I'm filing this bug in the wrong component, but I don't know where better to file it.)

I also tried downgrading to dvd+rw-tools-7.0-11.fc9, and that didn't help either.

This used to work.

I suppose it's possible that my hardware has gone south somehow, but it seems like something from rawhide being borked is a more likely explanation, so I thought I should file a ticket about it just in case...