Linux on MacBook Air with NVIDIA drivers

In order to use the proprietary NVIDIA driver on a MacBook Air 3,1 (11-inch, late 2010) with the NVIDIA GeForce 320M chipset booting openSUSE Leap 42.1 in EFI mode, create the file /etc/grub.d/01_enable_vga.conf with the following content:

#!/bin/sh
set -e

# Initialize the PCI-E registers of MBA 3,1 for the nvidia driver

cat << EOF
btrfs-mount-subvol /dev/sda3 /boot/grub2/x86_64-efi /@/boot/grub2/x86_64-efi
insmod setpci
setpci -s "00:17.0" 3e.b=8
setpci -s "02:00.0" 04.b=7
EOF

and run grub2-mkconfig -o /boot/grub2/grub.cfg to update the bootloader configuration. Be aware that you might need to determine the PCI bus ids for your machine first by running lshw -businfo -class bridge -class display as described in this post on askubuntu. (Please note that using only the setpci command as suggested in that post for Ubuntu systems does not suffice on openSUSE systems, because on this system the setpci functionality is provided as a separate GRUB module and must be loaded explicitly with the insmod command; since the GRUB modules are not installed on the boot partition, their location has to be mounted first using the btrfs-mount-subvol command.)

Reboot and verify that the settings have actually been applied by running the setpci command on the command line as root without the part after the equal sign (e.g. setpci -s "00:17.0" 3e.b). This should return the values assigned before, i.e. 8 or 7 respectively.

Then proceed installing the nvidia driver by choosing the appropriate package on the openSUSE Community website. In my case (NVIDIA GeForce 320M), that means choosing the „Geforce 8 series and later“ option.

 

My i3 dual screen workflow

Using the i3 tiling window manager on two screens („outputs“) can be challenging. The number of workspaces grows twice as fast than with a single screen setup and it is easy to lose track of the numbers and contents of workspaces. For me personally it is more intuitive to remember a certain sequence of workspaces on each screen, which seemingly extends above and below the workspace presently displayed. (It may be that this intuition has been coined by using the GNOME Shell over extended periods.)

In order to achieve a comparable user experience within i3, I use the following Python script with the keybindings presented below. The script is inspired by an article on the i3 homepage by user captnfab. It has one dependency: ziberna/i3-py, which can be installed with pip3 install i3-py. As is apparent from the keybindings, Ctrl+Alt+Up/Down are used to switch the present workspace on the focused output. With the same keys together with +Shift you can take the focused window with you.

#!/usr/bin/python3
#
# i3-switch-workspace.py
# by Fabian Stanke
#
# Sequentially switch workspaces on present output

import i3
import argparse

parser = argparse.ArgumentParser(
    description='i3 workspace switcher.')

parser.add_argument(
    '--move', action='store_true',
    help='take the focused container with you when moving.')
parser.add_argument(
    'direction', choices=['next', 'prev'],
    help='defines in which direction to switch.')

args = parser.parse_args()

workspaces = i3.get_workspaces()

# Determine focused workspace (and thus the focused output)
focused_ws = next((w for w in workspaces if w['focused']))

# Collect all workspaces of the focused output
ws_names = list(w['name'] 
                for w in workspaces 
                if w['output'] == focused_ws['output'])

# Determine position of focused worspace in that collection
idx = ws_names.index(focused_ws['name'])
target = focused_ws['name']

if args.direction == 'next':
	# Determine next workspace	

	if (idx + 1 < len(ws_names)):
		target = ws_names[idx + 1]
	else:
		# Determine last number used on this output
		maxidx = 1
		# Determine unused numbers 
		used = {}
		for w in workspaces:
			try:
				widx = int(w['name'])
				used[widx] = True
				if w['output'] == focused_ws['output']:
					maxidx = max(widx, maxidx)
			except:
				continue
		# Increment to create new name
		while used.get(maxidx, False):
			print(maxidx)
			maxidx += 1
		target = str(maxidx)


elif args.direction == 'prev':
	# Determine previous workspace

	if (idx - 1 >= 0):
		target = ws_names[idx - 1]
	#else remain at first workspace

if args.move:
	# Move the focused container to the target workspace first
	i3.command('move', 'container to workspace ' + target)

# Switch
#print("switch to " + target)
i3.workspace(target)

My preferred keybindings to actually use the above script are:

bindsym Ctrl+Mod1+Down exec i3-switch-workspace.py next
bindsym Ctrl+Mod1+Up exec i3-switch-workspace.py prev
bindsym Ctrl+Mod1+Shift+Down exec i3-switch-workspace.py --move next
bindsym Ctrl+Mod1+Shift+Up exec i3-switch-workspace.py --move prev

Rollback Debian Upgrade

A single Debian upgrade (apt-get upgrade) can be rolled back with the following command. The upgrade is identified by its date and time, which has to be looked up from /var/log/apt/history.log first.

grep -A 2 'Start-Date: 2016-06-26  17:38:49' /var/log/apt/history.log | tail -1 | sed -r -e "s/Upgrade: //" -e "s/([^:]+):amd64 \(([^,]+), [^,]+\),?/\1=\2/g" | xargs apt-get install