admin:linux:troubleshooting [~wiki]

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====== Troubleshooting Linux Problems ======

===== journal =====
The journal is where systems with the [[:admin:linux:systemd|systemd]] init system store their logfiles. ''[[:admin:linux:cli:journalctl|journalctl]]'' can show most of the errors occuring in the system.

===== SysRq =====
see also: [[https://www.kernel.org/doc/html/latest/admin-guide/sysrq.html|Linux Kernel documentation on SysRq]]

<code bash># enable all SysRq features
echo 1 | sudo tee /proc/sys/kernel/sysrq > /dev/null</code>

^ 2 | 0x2 | enable control of console logging level |
^ 4 | 0x4 | enable control of keyboard (SAK, unraw) |
^ 8 | 0x8 | enable debugging dumps of processes etc. |
^ 16 | 0x10 | enable sync command |
^ 32 | 0x20 | enable remount read-only |
^ 64 | 0x40 | enable signalling of processes (term, kill, oom-kill) |
^ 128 | 0x80 | allow reboot/poweroff |
^ 256 | 0x100 | allow nicing of all RT tasks |

===== solutions to common problems =====

==== CD burning doesn't work with BD burners ====
Try disabling Stream Recording, it's enabled by default in xfburn for all Blu-Ray writers and will kill your CDs. Only enable it with BDs.

==== encryption-related tasks take a long time ====
Install ''haveged'' for more entropy generation.

==== Plank panel doesn't show active applications ====
If you start the panel in the terminal the following error message can occur: ''g_dbus_proxy_set_default_timeout: assertion 'G_IS_DBUS_PROXY (proxy)' failed''

Solve it by starting plank via ''dbus-launch plank''.

==== changing permissions not allowed for user root ====
Immutable bit might be set.
<code bash>chattr -i</code>

==== D-Bus broker doesn't start properly ====
Possible error messages:

<code>
systemd[11487]: dbus-broker.service: Start request repeated too quickly.
systemd[11487]: dbus-broker.service: Failed with result 'protocol'.
systemd[11487]: Failed to start D-Bus User Message Bus.
gnome-keyring-daemon[11514]: couldn't connect to dbus session bus: Could not connect: Connection refused
dbus-broker-launch[1170]: Activation request for 'org.a11y.atspi.Registry' failed.
gkr-pam: unable to locate daemon control file
dbus-broker-launch[1290]: Activation request for 'org.a11y.atspi.Registry' failed.
dbus-broker-launch[1582]: Activation request for 'org.a11y.atspi.Registry' failed.
</code>

Solve with enabling D-Bus for the user:

<code bash>
systemctl --user enable dbus-daemon.service
</code>

==== GDBus.Error:org.freedesktop.portal.Error.Failed ====

Errors may include:

<code>
xdg-desktop-portal[2779]: Failed to create secret proxy
xdg-desktop-portal[2779]: Failed to get application states: GDBus.Error:org.freedesktop.portal.Error.Failed: Could not get window list
</code>

Solution: Remove ''xdg-desktop-portal(-gtk)'' packages.

==== AT-SPI related errors ====

<code>bamfdaemon[5470]: AT-SPI: Could not obtain desktop path or name
dbus-broker-launch[5425]: Activation request for 'org.a11y.atspi.Registry' failed.
bamfdaemon[5470]: atk-bridge: GetRegisteredEvents returned message with unknown signature
bamfdaemon[5470]: atk-bridge: get_device_events_reply: unknown signature
dbus-broker-launch[5425]: Activation request for 'org.a11y.atspi.Registry' failed.</code>

Solution: <code bash>rm /etc/xdg/autostart/at-spi-dbus-bus.desktop</code>

===== Drivers / Hardware =====

==== AMD RX Vega 56/64 ====
=== doesn't boot on Arch Linux ===
downgrade ''linux-firmware'' to version ''20181218.0f22c85-1''