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Cake day: June 10th, 2023

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  • I’d think so. 3k is so many pixels to compute and send 60 times a second.

    But this video says the effect on battery life in their test was like 6%, going from 4k to 800x600. I can imagine that some screens are better at saving power when running at lower resolutions… but what screen manufacturer would optimize energy consumption for anything but maximum resolution? 🤔 I guess the computation of the pixels isn’t much compared to the expense of having those physical dots. But maybe if your web browser was ray-traced? … ?!

    Also, if you take a 2880x1800 screen and divide by 2 (to avoid fractional scaling), you get 1440x900 (this is not 1440p), which is a little closer to 720p than 1080p.


  • I haven’t made a bridge to a VM before today, or made a bridge with Network Manager. That being said, I was able to persuade Network Manger to get a bridge working, and there are a few things I can note:

    • When you setup the bridge, the host network interface should become a slave to the bridge. This means that the physical network interface should not have an IP Address, and your bridge should now be where you configure the host’s IP address.

      • After you start the VM, you should be able to run ip link | grep 'master br0' on the host, and it should display 2 interfaces which are slaves to br0. One for the physical ethernet interface, one for the VM (vnet). And it should only list your ethernet interface when the VM is off.
    • The RedHat tutorial does not show the bridge and the host having different IP addresses, the RedHat tutorial shows the bridge and the guest having different IP addresses. Actually, no, the RedHat tutorial shows the libvirt NAT bridge, not even the bridge that the tutorial describes creating… If you set the IP address of virbr0, I don’t know what happens.

    • If your VM’s network adapter is connected to the host’s bridge, then you should be able to log into your VM and set a static IP address.

    I had a lot of problems getting Network Manager to actually use my ethernet interface as a slave for the bridge. Here’s what worked for me, though:

    nmcli con show
    nmcli con down 'Wired Connection 1'
    nmcli con modify 'Wired Connection 1' connection.autoconnect no
    nmcli con add type bridge con-name br0 ifname br0
    nmcli connection add type bridge-slave ifname enp7s0 master br0
    nmcli con modify br0 connection.autoconnect yes
    nmcli con modify bridge-slave-enp7s0 connection.autoconnect yes
    nmcli con modify br0 ipv4.method manual ipv4.addresses 172.16.0.231/24 bridge.stp no
    sudo systemctl restart NetworkManager.service
    nmcli con show
    ip addr
    
    • Instead of enp7s0, you’d use enp1s0 I guess.
    • Above, I manually set my bridge IP address to a static address because my ethernet interface is wired directly to another computer, so no DHCP for me. If you have DHCP on your ethernet network, you probably don’t need to set “ipv4.method” or “ipv4.addresses”.
    • I set “bridge.stp” to “no” because my network doesn’t have any redundant paths, and the stp process seems to take like 25 seconds before I can use the bridge network.

    After that, I can go into “Virtual Machine Manger”, set my VM’s NIC’s Network Source to “Bridge device…”, Device name to"br0", boot my VM, login to my VM, configure my VM’s ip address. And then I can connect to the VM’s IP address from the physical ethernet network.



  • POP!_OS apparently uses systemd-boot (not to be confused with systemd). It apparently adds a Windows entry automatically if Windows is installed on the same disk. When Windows is installed on a different disk, it looks like booting the windows boot manager EFI program is still possible with systemd-boot. The instructions given in that link are a bit vague, though.

    This page has a different, simpler approach and more specific steps. Apparently you can just copy the Microsoft EFI folder to a specific directory in your Linux drive’s ESP partition. I’d be a little bit concerned about Windows not being able to update its EFI bootloader, but I also don’t know if Windows ever updates that. The page also has instructions on how to interact with the systemd-boot menu during boot.

    You could also install grub yourself, but I can’t guarantee that’ll be easy. Mashing F2 might be the sanest solution, unless you plan on booting into Windows every day.


  • I got interested, so I spent some time looking into what’s going on here. I’m not intimately familiar with X11 or Wayland, but I figured out some stuff.

    Why sudo ip netns exec protected sudo -u user -i doesn’t work for X11 apps

    Short answer: file permissions and abstract unix sockets (which I didn’t know were a thing before now).

    File permissions: when I start an X11 login session, the DISPLAY is :0 and /tmp/.X11-unix/ has only 1 file X0. This file has 777 access. When I start my wayland session with Xwayland, the DISPLAY is :1 and /tmp/.X11-unix/ has 2 files X0 (777) and X1 (755). I can’t figure out how to connect to display :0, so I guess I’m stuck with :1. When you change to a different (non-root) user, the user no longer has access to /tmp/.X11-unix/X1.

    Abstract unix sockets: When I start my wayland/xwayland session, it creates abstract unix sockets with ids @/tmp/.X11-unix/X0 and @/tmp/.X11-unix/X1. See ss -lnp | grep Xwayland. The network namespace also sandboxes these abstract unix sockets. Compare socat ABSTRACT-CONNECT:/tmp/.X11-unix/X1 STDIN and sudo ip netns exec private socat ABSTRACT-CONNECT:/tmp/.X11-unix/X1 STDIN.

    When you do sudo ip netns exec protected su - user, you loose access to both the filesystem unix socket /tmp/.X11-unix/X1 and the abstract unix socket @/tmp/.X11-unix/X1. You need access to one or the other for X11 applications to work.

    I tried using socat to forward X1 such that it works in the network namespace… and it kinda works. sudo ip netns exec protected socat ABSTRACT-LISTEN:/tmp/.X11-unix/X1,fork UNIX-CONNECT:/tmp/.X11-unix/X1. It appears having ABSTRACT-LISTEN before UNIX-CONNECT is important, I guess it would be worth it to properly learn socat. With this sudo ip netns exec protected su - testuser -c 'env DISPLAY=:1 xmessage hi' works, but sudo ip netns exec protected su - testuser -c 'env DISPLAY=:1 QT_QPA_PLATFORM=xcb kcalc' does not work. 😞

    Changing the file permissions on /tmp/.X11-unix/X1 to give the user access seems to work better.

    Wayland waypipe

    Waypipe works as advertised. But it’s still a little bit tricky because you need to have two separate processes for the waypipe client and server, wait for the waypipe socket to be created, adjust file permissions for the waypipe socket file, and set (and probably mkdir) XDG_RUNTIME_DIR.

    waypipe -s /tmp/mywaypipe client &
    sleep 0.1
    chgrp shared-display /tmp/mywaypipe
    chmod g+w /tmp/mywaypipe
    sudo ip netns exec protected su - testuser -c 'mkdir -p -m 0700 /tmp/runtime-testuser && env XDG_RUNTIME_DIR=/tmp/runtime-testuser waypipe -s /tmp/mywaypipe server -- env QT_QPA_PLATFORM=wayland kcalc'
    kill -SIGINT %1
    

    Combined

    into this script https://github.com/vole-dev/grabbag/blob/main/run-netns-user-wayland.bash




  • Completely tangential tip, but in the very-limited video editing I’ve done recently: I’ve used Davinci Resolve, rendered as .mov, and then used ffmpeg to render to my actual desired format. e.g. h264 w/ aac audio so I can upload to Youtube:

    ffmpeg -i input.mov -c:v libopenh264 -profile:v high -c:a aac -pix_fmt yuv420p output.mp4

    I do think that finding the right flags to pass to ffmpeg is a cursed art. Do I need to specify the video profile and the pix_fmt? I don’t know; I thought I did when I adventured to collect these flags. Though maybe it’s just a reflection of the video-codec horrors lurking within all video rendering pipelines.

    edit: there may also be nvidia-accelerated encoders, like h264_nvenc, see ffmpeg -codecs 2>/dev/null | grep -i 'h\.264'. I’m not sure if the profile:v and pix_fmt options apply to other encoders or just libopenh264.



  • Shows for Winter 2024 on my radar, that I am interested in watching:

    • Classroom of the Elite: first two seasons were fun, looking forward to season 3
    • Bottom-tier Character Tomozaki: first season was OK, I’m interested in where the story will go
    • Mato Seihei no Slave: I vaguely recall someone saying there was something good about the source material
    • MASHLE: first season was OK, I’m not very interested in S2, I might binge it when the season is complete
    • Blue Exorcist: oh, another season. It’s been a while. I remember liking the first season and being confused at the start of the second season (it’s about 6 years between each season, so maybe I just forgot some important details. From a S2 MAL review: “the season does not follow the end of season 1. Episodes 18-25 were not canon and accordingly, they do not exist in season 2”, I didn’t know this, so maybe that was my problem)
    • The Dangers in My Heart: first season was fantastic, excited for the second season
    • A Sign of Affection: the source material is rated highly on MAL, I’ll give it a shot
    • Banished from the Hero’s Party: First season was OK
    • TSUKIMICHI: I liked the first season, looking forward to the second season
    • The Foolish Angel Dances with the Devil: I saw the PV, I’ll give it a shot
    • Cherry Magic!: The source material is rated well on MAL, I’ll give it a shot
    • The Witch and the Beast: The source material is rated well on MAL, I’ll give a shot
    • The Weakest Tamer Began a Journey to Pick Up Trash: WILDCARD, I dunno, it sounds like absolute trash from the title, but I think I’ll give it a shot anyways

  • Boushoku no Berserk was fairly enjoyable! It is kinda trash, but it’s good trash: there’s an actual plot, the main characters are fairly likeable and fairly believable (even if the villians are like “hahaha, watch me be evil!”) and have a touch of depth. The struggles that the MC has to deal with are actually interesting. The animation and sound design is of acceptable quality throughout. The voice acting was pretty good!

    7/10: guilty pleasure for those of us who like these kinds of shows. I generally know what I’m getting into when I see the promotional art and description for these kinds of shows; Boushoku no Berserk meets or exceeds those expections.

    Also Eris: “whoops, I guess I shouldn’t have gone along with Envy’s scheme.” A change of heart… but why? Because Fate won? lol. I guess just leave it up to the viewers imagination because the actual explanation would probably not be worth watching.




  • It doesn’t translate to “the undertaker”, I meant that it’s a nickname like “The Undertaker” is a nickname. Or “The Red Baron”, “Jack the Ripper”. That is to say, a nickname that conveys notoriety/fame rather than a nickname for your chums.

    From the Demon’s monologue the end of the episode:

    “I see. I remember now. It was Frieren. The mage who contributed significantly to humanity’s analysis of Zoltraak and slew more demons than anyone else in history. Frieren the Slayer (葬送のフリーレン). One of the geniuses I despise.”

    So we see that in the Crunchyroll translation (and I imagine the translation of the manga as well), 葬送のフリーレン gets 2 translations:

    • Title of the show: 葬送のフリーレン ➡️ Frieren: Beyond Journey’s End
    • Nickname of the character: 葬送のフリーレン ➡️ Frieren the Slayer

  • The way Demons think in this show is a lot like LLM Chat AIs like ChatGPT work. They don’t really think too much, not in the way humans do, but they excel at producing something that humans approve of. If you don’t probe them too much, they look just like humans. But if you probe too far you see that their behavior is a facade and that their underlying thoughts are not like humans, and they don’t necessarily even understand the words they use to appease humans. What happens when their facade improves? If a demon spent its entire life perfectly acting as a nice and thoughtful human, never causing any harm, would you still call it a monster?

    Demons and LLM Chat AIs differ in what their underlying thoughts are. LLM Chat AIs generally want approval. On the other hand, Demons want to survive and eat humans. They use language to manipulate humans and get what they want.





  • Update: I’ve now watched the available episodes of Berserk of Gluttony and Ragna Crimson. Both are good fun.

    Berserk of Gluttony so far has not been much more than an edgy fantasy power-fantasy. But it’s executed well and has been enjoyable. I think it’s a little darker than the typical power-fantasy. The bad-guys are laughably evil and I’m not sure if the plot is going anywhere interesting.

    Ragna Crimson is more story focused. I supposed this show also has the makings of a power-fantasy, but it has not leaned too heavily into the wish fulfillment aspect. The characters are more interesting. The bad-guys are also laughably evil here, but in a way that’s more pure (literally being monsters helps, I guess), and thus a bit more horrifying. Every reward has a price, and you often do not know what that price actually is.