Ubuntu missing web fonts.

After upgrading from Ubuntu 23.04 to 23.10 fonts on the web started looking weird. The solution was to install the microsofts fonts.

sudo apt-get install ttf-mscorefonts-installer

source: stackoverflow.com

Steam Deck missing stdio.h

I tried to compile an application for the steam deck when I ran into missing header files. Weirdly the correct packages seemed to be installed, so why was I missing headers?

A reddit post explained that Valve had deleted some files belonging to installed packages and the resolution was to reinstall them.

So I ran the following command and surely, my compile worked afterwards.

sudo pacman -S glibc linux-api-headers

Get full path for a file.

Time for another oneliner. I often need to get the full path of a file.
This can be done using the following command:

readlink -f myfile

Via stackoverflow.com

Text disappearing from context menus in Gnome

I'm having an issue where most text in Gnome disappears or gets corrupted. I'm yet to find the root cause.
In the meantime the best quickfix is to restart Gnome.

To do so, press alt + F2, type r and press enter.

Via linuxconfig.org

Add user to sudoers list

Just a simple oneliner.
usermod -aG sudo username

Via linuxize.com

Can't init device hci0: Connection timed out (110)

Bluetooth stopped working on my raspberry pi running raspbian. The first I tried was to reset the interface by running hciconfig hci0 down/up, but that gave me "Can't init device hci0: Connection timed out (110)".

I found that by removing the btusb module and then adding it back, I was able to get bluetooth working again. Next time bluetooth gives up, I will run this:
sudo hciconfig hci0 down
sudo rmmod btusb
sudo modprobe btusb
sudo hciconfig hci0 up
Via unix.stackexchange.com

Overclock works in Windows but hangs in Linux.

So I have this old Intel Lynnfield system from 2010. It's overclocked and has been so for many years. Works perfectly in Windows even during high load for several days. Ubuntu and other distributions I tried would randomly freeze. Even more strangely, it never happened during heavy load.

Maybe Linux uses some CPU instruction Windows doesn't and that particular instruction doesn't work with the overclock? I clocked the CPU down, but Linux would still hang randomly.
I upgraded the motherboard bios, I upgraded the GPU bios. I replaced the soundcard. I checked SMART data for the drives. I ran memtest. I tested with a different GPU vendor.
But I couldn't find what was going on. Why was it freezing, so randomly, when there was almost no load in the system?

But then, for some reason I checked the cpu frequency using /proc/cpuinfo. The CPU wasn't running at the speed I had specified in bios, it was clocking down. That could certainly explain why the system froze during low load scenarios. CPU scaling and overclocking seldom works well, but I had disabled the C-states in bios. I had disabled turbo in bios. I knew for a fact that this was the case, since I've checked it numerous times in Windows.

So I started searching about C-states and the Linux kernel. For some reason the kernel ignores whether the bios has turned off the c-states or not. Thus, my disabled C-states was enabled. Confusing and frustrating.

I tried to fix this by disabling cpu scaling within Ubuntu, but for some reason it never worked as it was supposed to. Then I found that there is a kernel parameter for specifying what level of C-state that is allowed.
intel_idle.max_cstate=1

So I opened up /etc/default/grub and modified the GRUB_CMDLINE_LINUX_DEFAULT:
GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_idle.max_cstate=1"

Then I ran
sudo update-grub2
sudo reboot

Finally I confirmed that the cpu was no longer scaling using
cat /proc/cpuinfo

If I understand it correctly (haven't verified), you can set the max_cstate to 0 to disable the intel_idle driver, which should make the kernel use the bios/uefi settings instead.

Sources:
Info from Dell
Info from IBM