Optical drive suffering from chronic premature ejection

My slot-loading optical drive (HP BDDVDRW CA21N) spins and up and then ejects every disc, a process that takes about 15 seconds. I've found lots of posts on enabling wanted ejects, but close to nothing on avoiding unwanted ones. I have tried commenting out the relevant line in

/etc/fstab

, and using

sysctl dev.cdrom.lock=1

, both making no change.

/sys/bus/scsi/devices/0\:0\:0\:0/device_b*

seems to always contain zeroes. Further system information follows:

brick@dowland:~$ uname -a
Linux dowland 5.10.0-9-amd64 #1 SMP Debian 5.10.70-1 (2021-09-30) x86_64 GNU/Linux

brick@dowland:~$ sudo modprobe sr_mod

brick@dowland:~$ sudo dmesg
...
[4251487.063009] sr 0:0:0:0: [sr0] scsi3-mmc drive: 24x/24x writer dvd-ram cd/rw xa/form2 cdda tray
[4251487.093385] debugfs: Directory 'sr0' with parent 'block' already present!
[4251487.093465] sr 0:0:0:0: Attached scsi CD-ROM sr0

brick@dowland:~$ lsscsi --long
[0:0:0:0]    cd/dvd  hp       BDDVDRW CA21N    C2S2  /dev/sr0 
  state=running queue_depth=1 scsi_level=6 type=5 device_blocked=0 timeout=30

brick@dowland:~$ cat /sys/bus/scsi/devices/0\:0\:0\:0/state
running

brick@dowland:~$ cat /sys/bus/scsi/devices/0\:0\:0\:0/uevent 
DEVTYPE=scsi_device
DRIVER=sr
MODALIAS=scsi:t-0x05

brick@dowland:~$ cat  /proc/sys/dev/cdrom/info 
CD-ROM information, Id: cdrom.c 3.20 2003/12/17

drive name:		sr0
drive speed:		24
drive # of slots:	1
Can close tray:		1
Can open tray:		1
Can lock tray:		1
Can change speed:	1
Can select disk:	0
Can read multisession:	1
Can read MCN:		1
Reports media changed:	1
Can play audio:		1
Can write CD-R:		1
Can write CD-RW:	1
Can read DVD:		1
Can write DVD-R:	1
Can write DVD-RAM:	1
Can read MRW:		1
Can write MRW:		1
Can write RAM:		1

Thank you for reading this far! What else should I look at?