Writing to a USB cd/dvd drive fails, with both CD-RW and DVD+RW media
if "hi" speed USB (ehci) is configured into the kernel.
Reading at hi speed works.

=============

The slow, working, version, with DVD+RW media:

growisofs -Z /dev/rcd0c=netbsd_alphacd.iso > log_write_dvd_slowusb 2>&1

About to execute 'builtin_dd if=netbsd_alphacd.iso of=/dev/rcd0c obs=32k seek=0'
Sleeping for 5 sec...4 sec...3 sec...2 sec...1 sec...0 sec...
/dev/rcd0c: "Current Write Speed" is 4.1x1385KBps.
   1671168/150470656 ( 1.1%) @0.3x, remaining 8:54
   3964928/150470656 ( 2.6%) @0.7x, remaining 4:55

     [ ... ]

 146178048/150470656 (97.1%) @0.5x, remaining 0:06
 148471808/150470656 (98.7%) @0.5x, remaining 0:02
/dev/rcd0c: flushing cache
/dev/rcd0c: stopping de-icing
/dev/rcd0c: writing lead-out
/dev/rcd0c: reloading tray

=============

But with "hi" speed USB configured:

Executing 'builtin_dd if=netbsd_alphacd.iso of=/dev/rcd0c obs=32k seek=0'
/dev/rcd0c: "Current Write Speed" is 4.1x1385KBps.
:-( unable to WRITE@LBA=1c0h: Input/output error
:-( write failed: Input/output error
/dev/rcd0c: flushing cache
/dev/rcd0c: stopping de-icing
/dev/rcd0c: writing lead-out
/dev/rcd0c: reloading tray

and dmesg says::

	cd0(umass0:0:0:0): unknown error category 8 from adapter

=============

Alpha, 164lx, running NetBSD 2.0

fwohci0 at pci2 dev 8 function 0: NEC uPD72871 IEEE 1394 OHCI Host Controller (rev. 0x01)
fwohci0: interrupting at eb164 irq 14
fwohci0: OHCI 1.0, 00:00:4c:01:00:00:00:00, 400Mb/s, 1024 max_rec, 4 ir_ctx, 4 it_ctx
ohci0 at pci2 dev 9 function 0: NEC USB Host Controller (rev. 0x41)
ohci0: interrupting at eb164 irq 18
ohci0: OHCI version 1.0
usb0 at ohci0: USB revision 1.0
uhub0 at usb0
uhub0: NEC OHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub0: 3 ports with 3 removable, self powered
ohci1 at pci2 dev 9 function 1: NEC USB Host Controller (rev. 0x41)
ohci1: interrupting at eb164 irq 3
ohci1: OHCI version 1.0
usb1 at ohci1: USB revision 1.0
uhub1 at usb1
uhub1: NEC OHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub1: 2 ports with 2 removable, self powered
ehci0 at pci2 dev 9 function 2: NEC USB Host Controller (rev. 0x02)
ehci0: interrupting at eb164 irq 10
ehci0: EHCI version 0.95
ehci0: companion controllers, 3 ports each: ohci0 ohci1
usb2 at ehci0: USB revision 2.0
uhub2 at usb2
uhub2: NEC EHCI root hub, class 9/0, rev 2.00/1.00, addr 1
uhub2: 5 ports with 5 removable, self powered

umass0 at uhub2 port 2 configuration 1 interface 0
umass0: Prolific Technology Inc. ATAPI-6 Bridge Controller, rev 2.00/0.01, addr 2
umass0: using SCSI over Bulk-Only

scsibus1 at umass0: 2 targets, 1 lun per target
cd0 at scsibus1 target 0 lun 0: <HL-DT-ST, DVDRAM GSA-4160B, A301> cdrom removable