bin/51331: cdrom will not mount after first time

[scole_mail%gmx.com@localhost]

>Number:         51331
>Category:       bin
>Synopsis:       cdrom will not mount after first time
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Jul 10 17:35:00 +0000 2016
>Originator:     scole_mail
>Release:        7.0.1
>Organization:
none
>Environment:
NetBSD dstar 7.0.1_PATCH NetBSD 7.0.1_PATCH (GENERIC) #0: Sat May 28 11:24:19 EDT 2016  scole@dstar:/home/scole/nbsd/7_0/obj/sys/arch/i386/compile/GENERIC i386
>Description:
My cdrom drive seems only to be able to mount a cd 1 time.  After that
I need to reboot the machine to use it:

dstar# mount /cdrom
dstar# df /cdrom
Filesystem    1K-blocks       Used      Avail %Cap Mounted on
/dev/cd0a           358        358          0 100% /cdrom
dstar# umount /cdrom

The eject button on cd-drive doesn't work anymore after that, but
doing

dstar# eject -v cdrom
device type == disk, floppy, or cdrom
Ejecting /dev/rcd0d...
done.

will eject it.  But, then trying to remount again won't work anymore

dstar# mount /cdrom
mount_cd9660: /dev/cd0a on /cdrom: Device not configured

A reboot then seems required to mount the CD again.

My fstab contains this for the cdrom
 /dev/cd0a               /cdrom  cd9660  ro,noauto

and dmesg output

cd0 at atapibus0 drive 0: <HL-DT-STDVD-RAM GH22NS30, , 1.00> cdrom removable
cd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 5 (Ultra/100)
cd0(ahcisata0:2:0): using PIO mode 4, DMA mode 2, Ultra-DMA mode 5 (Ultra/100) (using DMA)

Thanks

>How-To-Repeat:
Insert cdrom, mount cdrom, unmount cdrom, eject cdrom, try to mount cdrom again
>Fix: