Ways of Using NVIDIA Graphics Card in a Linux Machine

There are different ways of using NVIDIA graphics drivers in Linux machine, such as:
1. Using it as the main GPU
Cons:
a. Significantly more power consumption compared to using Intel HD
b. Known artifacts, which is sometimes portion of the screen gets corrupted. This goes away when mouse is hovered over, but is still annoying

2. Using it with Bumblebee to get PRIME-like feature.
As most of you are probably familiar, in Windows, the default setting is that NVIDIA GPU is turned on only if it's needed. For example when you're running a game, it's turned on, but when you're browsing, editing a text-file, or something else lightweight, it's turned off to conserve the battery. In Linux, however, such feature doesn't work. The open-source community, however, created an effort to get a similar feature: Bumblebee project. With Bumblebee, Intel HD is the one that renders to the screen. NVIDIA GPU, when requested, is used to render things to a transparent layer, which is then transported into the Intel HD buffer to be rendered to the screen. Unliked PRIME feature in Windows, however, the switch between when to use NVIDIA vs. Intel is not automated. You'll have to specifically tell a program to use which GPU.
For more information: https://github.com/Bumblebee-Project/
Cons:
a. Setup can be pretty complex
b. The perf is not as good as using NVIDIA to render directly to the screen, because of the additional step of transporting NVIDIA-rendered buffer to screen buffer, which is a CPU-consuming step

3. Using nvidia-xrun to run a separate entity of X server which uses NVIDIA GPU.
This is actually my favorite, because this is very easy to setup. To give a little bit of background, in Linux, there is a component called Display Manager the job of display manager is to provide an interface for application to render stuffs onto the screen. In other words, it's a bridge between application and display hardware. And for any applications to render significant graphics into the screen, they use the API provided by X server. So the idea here is to run 2 separate X servers. The first is used to run typical lightweight workload such as text-editing, web-browsing, etc, and is backed by Intel HD drivers. The second is backed by NVIDIA drivers, hence is using the NVIDIA card, and is only run when there is a need to run an application that requires it. So this is very similar to Bumblebee project, except is much simpler.



Special thanks to:
https://wiki.archlinux.org/index.php/NVIDIA
https://github.com/Witko/nvidia-xrun
https://github.com/Bumblebee-Project/

Recoving Arch Linux Failed System Upgrade

Once in a while, it's nice to do a complete system upgrade in Arch Linux. All the packages will be updated to the latest bleeding edge release.

However, if for some reason the package upgrade failed, perhaps due to power outage or something unexpected. In my case, I left my system upgrading over night, and unfortunately, in the morning the screen is all black and nothing works. I tried rebooting, but even GRUB didn't show up!

Upgrading arch system

# Beware this might take a long time to run. Could be a few hours. sudo pacman -Syu

Fixing Corrupted Upgrade

1. Boot to Ubuntu live CD
2. Figure out partition where your Arch is installed
sudo fdisk -l
3. Mount the partition
sudo mount /dev/sdaX /mnt
4. Mount devices
mount -t proc /proc mnt/proc
mount --rbind /sys mnt/sys
mount --rbind /dev mnt/dev
5. Chroot to Arch, this basically is to get into Arch system using the current Ubuntu's kernel
sudo chroot /mnt
6. Now that you're inside of your Arch, you can do whatever needed to fix your installation. Below are some stuffs that might be needed
# Finish unfinished Arch upgrade.
# To see if you need this, check /var/log/pacman.log. There you'll see what happened on your last upgrade. (i.e. upgrade got interrupted in the middle) sudo pacman -Syu

# Re-create RAM disk, this creates device initialization configuration that kernel uses to boot
# For more info: https://wiki.archlinux.org/index.php/mkinitcpio
sudo mkinitcpio -p linux

# Fix GRUB installation. In my case, GRUB didn't show up on boot, so perhaps it was corrupted or something
sudo grub-mkconfig > /boot/grub.cfg # Unlike in normal environment, /boot here is mounted as RW, so write here will persist
# P.S: If you dual boot Arch with other distro, mount the other distro before running grub-mkconfig. If you do so
# GRUB will automatically detect it and create appropriate entry in bootloader

7. Reboot your system! :)
Hopefully this is helpful. Much thanks to Mort Yao's article: https://www.soimort.org/notes/170407/