Comment 0 for bug 1794308

Linux s390x as VM guest can use the VM-specific reader (0.0.000c), puncher (0.0.000d) and printer devices (0.0.000e).

They can be enabled as usual with chzdev like:
lszdev | grep '000c\|000d\|000e'
generic-ccw 0.0.000c no no
generic-ccw 0.0.000d no no
generic-ccw 0.0.000e no no
sudo chzdev -e 000c 000d 000e
Generic CCW device 0.0.000c configured
Generic CCW device 0.0.000d configured
Generic CCW device 0.0.000e configured
lszdev | grep '000c\|000d\|000e'
generic-ccw 0.0.000c yes yes vmrdr-0.0.000c
generic-ccw 0.0.000d yes yes vmpun-0.0.000d
generic-ccw 0.0.000e yes yes vmprt-0.0.000e

Aa a result of that activation udev rules are generated:
ls -la /etc/udev/rules.d/41-generic-ccw-0.0.000{c,d,e}.rules
-rw-r--r-- 1 root root 238 Sep 21 06:24 41-generic-ccw-0.0.000c.rules
-rw-r--r-- 1 root root 238 Sep 21 06:24 41-generic-ccw-0.0.000d.rules
-rw-r--r-- 1 root root 238 Sep 25 10:15 41-generic-ccw-0.0.000e.rules
cat /etc/udev/rules.d/41-generic-ccw-0.0.000{c,d,e}.rules
# Generated by chzdev
ACTION=="add", SUBSYSTEM=="ccw", KERNEL=="0.0.000c", GOTO="cfg_generic_ccw_0.0.0
00c"
GOTO="end_generic_ccw_0.0.000c"

LABEL="cfg_generic_ccw_0.0.000c"
ATTR{[ccw/0.0.000c]online}="1"

LABEL="end_generic_ccw_0.0.000c"
# Generated by chzdev
ACTION=="add", SUBSYSTEM=="ccw", KERNEL=="0.0.000d", GOTO="cfg_generic_ccw_0.0.0
00d"
GOTO="end_generic_ccw_0.0.000d"

LABEL="cfg_generic_ccw_0.0.000d"
ATTR{[ccw/0.0.000d]online}="1"

LABEL="end_generic_ccw_0.0.000d"
# Generated by chzdev
ACTION=="add", SUBSYSTEM=="ccw", KERNEL=="0.0.000e", GOTO="cfg_generic_ccw_0.0.0
00e"
GOTO="end_generic_ccw_0.0.000e"

LABEL="cfg_generic_ccw_0.0.000e"
ATTR{[ccw/0.0.000e]online}="1"

LABEL="end_generic_ccw_0.0.000e"

Once this is done it's expected that this configuration is persistent and that these three devices are automatically activated after a reboot, which is not the case:

lszdev | grep '000c\|000d\|000e'
generic-ccw 0.0.000c no yes
generic-ccw 0.0.000d no yes
generic-ccw 0.0.000e no yes

A 'sudo udevadm trigger' doesn't help to activate them again.

Another 'sudo chzdev -e 000c 000d 000e' helps, but again for the current session only.

[
The cio_ignore list is empty, hence this can't be the reason:
cio_ignore -l
Ignored devices:
=================
$
]