Problem with all of them: Drivers get mental thinking its a TABLET ! The Laptop is no tablet ....
Applies to Ubuntu, Xubuntu, ... 18.x, 19.x, 20.x, 21.x, 22.04
THANKs to the may great, smart, encouraged, skilled people who invented all the details I collect and stuff together in the following as a solution proven to work in my machines - might their well being last forever.
be warned:
There is a substantial issue with GSM modems in Ubuntu 22.04 !
All former releases (18.x, 20.x, 21 up to 21.10) and all flavors (XFCE4) before 22.04 are not concerned.
IPv6 does not work at all over GSM.
The issue causes interdependencies with WiFi control, too.
Switching off WiFi breaks the GSM connect.
Disabling modem-manager does not resolve it.
Modem is Sierra Wireless, Inc. EM7421
you are well advised to upgrade the firmware but thats not related to the ubuntu bug.
Problem:
Ubuntu (18, 19, 10, 22, ...) with Gnome GUI crashes if you boot the machine and do not log into the GUI.
Precondition:
There is a GUI (should not apply to mere server installations)
Mostly some Gnome. Other flavours like "Ubuntu" or "Unity" may be concerned the same way. X and Wayland.
Symptoms:
GUI crashes completely after some 20 or so minutes.
Machine can not be reached by ssh any longer (often, not always, may vary).
Does not help:
Adjust the plenty of settings available via dconf-editor.
Nothing helps.
The issue:
I do not have / lost executable rights in my /home. Which is quite devastating for TOR onion use. This pops up on increasing number of machines with Ubuntu 20.xxSome new set up and some worked with existing exec rights before .
Situation:
/dev/mapper/luks-12345 /home ext4 exec,rw,users 0 2) but
it is IGNORED.Mount is reported as:
/home /dev/mapper/luks-12345 ext4 rw,nosuid,nodev,**noexec**,relatime
although set as exec in fstab.
Question:
Example executed in ~:
$ ./myscript.sh
bash: ./myscript.sh: Keine Berechtigung (translate: no rights)
same old script after rw remount:
- just executing -
Remarks:
Setup of encrypted /home is shown here (use TOR; German only): http://mutant21.onastroidst6krpn.onion/schweinekraftland/Verschluesseln01/Verschluesselung_nachtraeglich_umsetzen.htm All file systems are ext4. It appears on several machines. Earliest identified OS rel. is Ubuntu 20.04 since mid of 2020.
mount version: util-linux 2.36 libmount 2.36.0
Looks to me like a bug, no doc found: If you remove the mount option "users" the problem will not occur. This must have changed mid 2020 since it definitely worked early 2020 to have option "users" and a mount with applied exec rights. Does not explain why "exec" option is just ignored when used in fstab the regular way.
Addendum:
mount version 2.34 does not show the error. Using mount version 2.36 causes the error, reproducible. Does not explain the bug but it explains the timeline of occurence.
Since the recent update from 20.04 to 20.10 cryptsetup fails to open luks container.
Message is:
> Cannot use twofish-ecb cipher for keyslot encryption. Keyslot open
> failed. No usable keyslot is available.
isLuks
is positive,
cryptsetup -v luksDump /dev/sdx3
brings the expected results, perfect.
issue:
sudo cryptsetup luksOpen /dev/sdx3 luks-61[...]51
successfully requests and accepts passphrase then fails with
> Cannot use twofish-ecb cipher for keyslot encryption.
> Keyslot open failed.
> No usable keyslot is available.
Subsequently /dev/mapper does not show this luks mapping while still working fine for the other luks mappings.
Only special thing about /dev/sdx is: it is a btrfs/gpt disk. Working fine with Ubuntu, Fedora, Suse until the upgrade. After the incident started, a resize under Fedora 32 worked fine, no issues (remarkable for shrinking a gpt/btrfs/LUKS partition).
Used to work fine under Ubuntu 20.04 (until the reboot after upgrade to 20.10).
no problem in kern.log BEFORE the upgrade:
Oct 18 16:14:47 kurt kernel: [ 24.243562] BTRFS: device label bxxxxxxxx_crypt devid 1 transid 612 /dev/dm-2
Oct 18 16:14:47 kurt kernel: [ 24.269818] BTRFS info (device dm-2): use zlib compression, level 3
Oct 18 16:14:47 kurt kernel: [ 24.269820] BTRFS info (device dm-2): disk space caching is enabled
Oct 18 16:14:47 kurt kernel: [ 24.269821] BTRFS info (device dm-2): has skinny extents
comparing other flavours: Version with U20.10: cryptsetup 2.3.3 (not working, however) Working with Suse 15.1, cryptsetup 2.0.6 and working with Fedora 32, cryptsetup 2.3.4 and used to work with U20.04, cryptsetup 2.2.2 AFAIK.
Why does it fail under Ubuntu 20.10? What can I do to fix it?
dmesg messages are spamed with gazillions of entries like:
[drm:gen9_set_dc_state [i915]] Setting DC state from 02 to 00
[drm:intel_power_well_enable [i915]] enabling DC off
and then back
[drm:skl_enable_dc6 [i915]] Enabling DC6
[drm:gen9_set_dc_state [i915]] Setting DC state from 00 to 02
on my laptop having Intel i915 GPU and Ubuntu latest.
Some messages per fraction of a second. dmesg is unusable this way. I want to stop that.
What I found: The built in Intel i915 graphics can be controlled by Kernel parameters like i915.disable_power_well.
Intel explains:
disable_power_well:Disable display power wells when possible (-1=auto [default], 0=power wells always on, 1=power wells disabled when possible) (int)
My problem: As a non native speaker I do not get the gist of "display power wells". Can someone please tell me the meaning of Intel "power wells"?
I intend to change this unacceptable behaviour by using kernel parameter
i915.disable_power_well= ....
What value is most appropriate?
In Xubuntu 18.x and Ubuntu XFCE 19.04, 19.10 (XFCE4, lightdm) I experience the un-lock screen does not show up. The screen remains locked!
Actually typing the password into the invisible lock sceen OPENS the lock!!!
That means the password request is working but does not show up. This is the reason why there are no error messages.
"light-locker-settings" explicitly tells me XFCE is controlling the "energy" settings. This works.
And there is no cover window over the GUI when it is "locked". The window in front of the main GUI does not show up (information not covered) and password entry does not show up.
QUESTION: How can I make the password request visible again??
Problem:
~$ simple-image-reducer
Traceback (most recent call last):
File "/usr/bin/simple-image-reducer", line 28, in <module>
import Image
ImportError: No module named Image
Reason:
Image != image
I need to install Ubuntu 19 o. 20 o. 21 o. 22 on a quite recent machine.
I enabled all compatibility and legacy modes in BIOS to avoid UEFI. (DO THAT FIRST!!!)
I do not want to use UEFI.
The installation media (Ubuntu - ISO put on a USB-stick using dd) wants to force UEFI boot mode.
I want simple mbr and grub boot (although Lilo was so much better than grub). I totally decline to use UEFI.
How can I install Ubuntu without UEFI?
The virtual PDF printer is no longer available. It was based on cups-pdf. Since 18.04 it is gone. No error message. Just disappeared in GUI for printer control. Worked fine before the upgrade.
New install of cups-pdf is possible but does not help. It tells:
[...]
Note, selecting 'printer-driver-cups-pdf' instead of 'cups-pdf'
printer-driver-cups-pdf is already the newest version (3.0.1-5).
[...]
But not a trace of PDF printer functionality in the gui printer setup. Applications do no longer show the cups-pdf "printer".
Question: How can I get the (cups-) pdf back in 18.04? Is there a workaround?
Windows 10 - Ubuntu 15.10 dual: No Ubuntu after W10 shutdown, not restart
Problem:
If I do restart Win10 and start Ubuntu (instead of W10) the Grub starts Ubuntu 15.10 without issues.
If I shutdown Windows 10 instaed, Ubuntu does not boot. Grub starts, then total failure. No visible reason.
I can reproduce it as often as I like.
Starting Windows 10 after that incident is fine!
Starting Ubuntu does NOT work at all....
EXCEPT I shut down Windows-10 with a RESTART.
Problem:
Windows 10 - Ubuntu 15.10 dual boot gets f***ed up by Windows 10. No Ubuntu after W10 shutdown.
Why??
SOLUTION / The answer is: The Windows 10 shutdown is NO shutdown. It is a hibernation state. The boot sector gets poisoned by Windows-10 after entering the Hibernation state and shutting down the hardware.
So Grub / Ubuntu can not handle it, the boot sect is malformed.
Solution:
Go to Windows 10 settings and disable the Fast Boot option in the Energy settings.
In German it is "Schnellstart aktivieren (empfohlen)". NO NOT CHECK!!! This option kills Ubuntu boot!
Sie finden diese Einstellung in Windows-10 Energieoptionen / Systemeinstellungen / Einstellungen fuer das Herunterfahren als ersten Punkt.
Then it works fine.
Applies to earlier Windows 8 and 7 too.