wifi error for raspberry: brcmfmac: brcmf_set_channel: set chanspec 0x100e fail, reason -52

Origin link 2024-9-20

I couldn't connect to my raspberry pi for several days. Today I conducted a trouble shooting.

At beginning, I think system is down due to flashcard broken but later I found raspyberry still has ipv4/ipv6 address from home router. I tried to ssh but not successful. I ping the server first, ping is Ok. Then I could ssh server successfully.

it seems i am not the only guy who has this issue, see

https://forums.raspberrypi.com/viewtopic.php?t=367466

https://askubuntu.com/questions/1508490/ubuntu-server-on-raspberry-pi-5-is-not-connecting-to-the-internet

python typing check

Origin link 2024-8-1

Docstring Linter

pydocstyle

Style Linter

pylint
pycodestyle

Error Linter:

pyflake
pylint

Complexity Analysis

mccabe

flake8

flake8 = Pyflakes + pycodestyle + mccabe

type checker:

mypy

run it on command line
run it with language server, for example: pylsp
run it with Jupyter

nb-mypy: configure it with ipython configuration or run it with command in jupyter

jupyter-lsp + pylsp

Language server

pyls and pylsp
prefer to use pylsp instead of pyls, see link for detail.

difference between different linter tools

Pylint vs Pyflakes vs Flake8 vs autopep8 vs Bandit vs Prospector vs Pylama vs Pyroma vs Black vs Mypy vs Radon vs mccabe

racket

Origin link 2024-3-17

racket is one of scheme dialect and I want to use racket to learn "the litte schemer". One of problem I meet is how to load file with scheme code (not racket code) into REPL and run relate function. In guile, it is very simple: guile -l my_function.scm. but in racket, it is little complex.

with load (traditional scheme file, no #lang)

it could work "racket -if <my_function.scm>" but my_function.scm should not start with "#lang racket". it is same with load function.

with module (racket file, with #lang)

Racket has concept of module, every file is module and each module need "initial-module-path" which is "The #lang at the start of a module file begins a shorthand for a module form"

First, like import in python, you could use (require my_function.scm) in source code and "-t " in command line to import a module, but you need to list which function is export by (provide function) in my_function.scm, or (provide (all-defined-out)) to export all functions.

-t <file>, --require <file> Like -e '(require (file "<file>"))' [*]

Another trick point is you need "racket -i -t my_function.scm" instead of "racket -t my_function.scm -i". I don't know why but I guess it is related to "If -t/-l/-p/-u appears before the first -i/-e/-f/-r, -n is added".

Second, you could config initial-module in command line with "racket -I typed/racket" (#lang typed/racket in source code). The magic of of initial-module-path is you could define a new language with different syntax.

Third, you could always start "racket -i" and use ",enter my_function.scm" or "racket -i -e '(enter! "my_function.scm")'" to go to my_function namespace.

git remote repository with bare

Origin link 2023-12-1

if you want a remote repository and put local source into remote, you need to set up remote repository with "git init bare . ", not "git init ."

link1, link2

xmlrpc on rtorrent

Origin link 2023-11-24

rotorrent could use xmlrpc to send command remotely without any ui interface.

how to setup xmlrpc support (link, link2 )

configure scgi port on rtorrent.rc
install nginx and setup location for scgi and configure same scgi port from rtorrent.rc
rtorrent from Archlinux has dependency (libxmlrpc from http://xmlrpc-c.sourceforge.net/). there is binary application in this package to send xmlrpc command to rtorrent

xmlrpc basic

xmlrpc is specification for request sent to client (link)
xmlrpc has scalar (int,boolean, string, double), struct (dictionary), array.
xmlrpc binary command convert command parameter into request. Different binary command has different command parameter but request is same.
for xmlrpc (http://xmlrpc-c.sourceforge.net/), it need to escape ":" as "\:" since ":" is separator for struct. (link ). The parenthesis, brace, comma, colon, and backslash characters are special. If you want to include one in a string value, escape it with a backslash.

usag

"2838954B0BBB1A87A668308DCC08AAF56D83D20D" is infohask for one rtorrent.
"2838954B0BBB1A87A668308DCC08AAF56D83D20D\:t0" is tracker1 for one rtorrent.
xmlrpc localhost system.listMethods
xmlrpc localhost system.methodHelp t.id
xmlrpc localhost load.normal "magnet:?xt=urn:btih:59066769B9AD42DA2E508611C33D7C4480B3857B&dn=ubuntu-17.04-desktop-amd64.iso&tr=http%3A%2F%2Ftorrent.ubuntu.com%3A6969%2Fannounce&tr=http%3A%2F%2Fipv6.torrent.ubuntu.com%3A6969%2Fannounce"
xmlrpc localhost download_list
xmlrpc localhost d.is_open 2938964B0BAB1A87A668308DCC08AAF56D83C20D
xmlrpc localhost d.state <hash>
xmlrpc localhost d.chunk_size 2838954B0BBB1A87A668308DCC08AAF56D83D20D
xmlrpc localhost d.size_files "BBAB39AF48A4BD6FD23F1CCA39246A3E9D22F76B"
xmlrpc localhost d.size_chunks "BBAB39AF48A4BD6FD23F1CCA39246A3E9D22F76B"
xmlrpc localhost d.size_bytes "BBAB39AF48A4BD6FD23F1CCA39246A3E9D22F76B"
xmlrpc localhost d.completed_chunks "BBAB39AF48A4BD6FD23F1CCA39246A3E9D22F76B"
xmlrpc localhost d.complete 2838954B0BBB1A87A668308DCC08AAF56D83D20D
xmlrpc localhost d.ratio 2838954B0BBB1A87A668308DCC08AAF56D83D20D
xmlrpc localhost d.down.total 2838954B0BBB1A87A668308DCC08AAF56D83D20D
xmlrpc localhost d.down.rate 2838954B0BBB1A87A668308DCC08AAF56D83D20D
xmlrpc localhost d.up.total 2838954B0BBB1A87A668308DCC08AAF56D83D20D
xmlrpc localhost d.up.rate 2838954B0BBB1A87A668308DCC08AAF56D83D20D
xmlrpc localhost p.multicall 2838954B0BBB1A87A668308DCC08AAF56D83D20D p.id
xmlrpc localhost d.tracker.insert 2838954B0BBB1A87A668308DCC08AAF56D83D20D 0 "udp\://tracker.openbittorrent.com\:80"
xmlrpc localhost d.tracker.insert 2838954B0BBB1A87A668308DCC08AAF56D83D20D 1 "udp\://tracker.opentrackr.org\:1337/announce"
xmlrpc localhost d.tracker_size 2838954B0BBB1A87A668308DCC08AAF56D83D20D
xmlrpc localhost t.id <hash>
xmlrpc localhost t.is_open "2838954B0BBB1A87A668308DCC08AAF56D83D20D\:t1"
xmlrpc localhost t.id "2838954B0BBB1A87A668308DCC08AAF56D83D20D\:t0"
xmlrpc localhost f.multicall "BBAB39AF48A4BD6FD23F1CCA39246A3E9D22F76B" "*" f.path=
xmlrpc localhost f.frozen_path "BBAB39AF48A4BD6FD23F1CCA39246A3E9D22F76B\:f2"
xmlrpc localhost f.path "BBAB39AF48A4BD6FD23F1CCA39246A3E9D22F76B\:f3"
xmlrpc localhost f.completed_chunks "BBAB39AF48A4BD6FD23F1CCA39246A3E9D22F76B\:f2"
xmlrpc localhost f.size_bytes "BBAB39AF48A4BD6FD23F1CCA39246A3E9D22F76B\:f2"

WSL with gpu accelerator and webgpu

Origin link 2023-11-24

GPU accelerator on WSL need WDDM 2.9 (link ). Windows 10 support WDDM from 20H2 (link) but Intel driver only support WDDM > 2.9 from Windows 11 (link). You could use "dxdiag" to check WDDM version on your windows.

My laptop is Intel GPU + Windows 10. Intel driver doesn't support WDDM v2.9 or later on Windows 10 but it is OK on Windows 11. It means WSL couldn't support GPU accelerator on Windows 10.

If you want to use webgpu under wsl2, use following chrome command since webgpu on chrome only support vulkan now according to Chrome ships WebGPU.

"--enable-unsafe-webgpu --enable-features=Vulkan --use-vulkan=swiftshader"
"This initial release of WebGPU is available in Chrome 113 on ChromeOS devices with Vulkan support, Windows devices with Direct3D 12 support, and macOS. Linux, Android, and expanded support for existing platforms will come soon."

GCC

Origin link 2023-4-26

some tips when i trying compile opengl programs in conda

g++ -I/home/hongy19/miniconda3/envs/opengl/include/ : include *.h
g++ -L/home/hongy19/miniconda3/envs/opengl/lib :add folder of *.so for link(ld)
g++ -lglfw: use libglfw.so for link(ld)
LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/hongy19/miniconda3/envs/opengl/lib ./a.out: add library search path for dynamic *.so
static compile

-static compile for static link need *.a and *.o library and *.so doesn't work for static compile, see link. The error of following code is due to missing of *.a or *.o even *.so existed.

(opengl) hongy19@WSL opengl$ gcc glfw-1.cpp -static -lglfw -lGL
/usr/sbin/ld: cannot find -lglfw: No such file or directory
/usr/sbin/ld: cannot find -lGL: No such file or directory
collect2: error: ld returned 1 exit status

pkgconfig

PKG_CONFIG_PATH=$CONDA_PREFIX/lib/pkgconfig pkg-config --list-all
PKG_CONFIG_PATH=$CONDA_PREFIX/lib/pkgconfig pkg-config --cflags glfw3 -I/home/hongy19/miniconda3/envs/opengl/include
PKG_CONFIG_PATH=$CONDA_PREFIX/lib/pkgconfig pkg-config --cflags gtk+-3.0

X11 and wayland

Origin link 2023-4-22

see Environment variables for Wayland hackers and Wayland-specific environment variables for detail and what is setting in wsl2.

WAYLAND_DISPLAY

wayland unix socket
WAYLAND_DISPLAY=wayland-0

XDG_RUNTIME_DIR

directory of wayland unix socket
XDG_RUNTIME_DIR=/mnt/wslg/runtime-dir/ or XDG_RUNTIME_DIR=/run/user/1000/

DISPLAY

X11 unix socket
DISPLAY=:0 and /tmp/.X11-unix/X0

GDK_BACKEND

it is better to set according to GTK backend selection, or why GTK cannot open display: :0
If the special value of help is used, a GTK application will print the possible values it knows. see link.

gtk3/gtk3 in conda has disabled wayland support, see link.

with pygobject, GDK_BACKEND=wayland doesn't work but chrome/weston-terminal is OK and pygobject is OK with GDK_BACKEND=wayland, x11 or GDK_BACKEND=x11.
with GDK_BACKEND=help, gtk3 only support x11, not wayland
condas gtk3.0/gtk4.0 only support x11, not wayland since no ~/miniconda3/envs/gtk/include/gtk-3.0/gdk/gdkwayland.h.

(gtk) hongy19@WSL cairo$ GDK_BACKEND=help python test1.py

Supported GDK backends: x11

keyboard

Origin link 2023-4-16

According to Archlinux wiki and How Keys Are Turned Into Actions , here comes how keystroke information is transferred in computer.

Keyboard send scancode to computer
Linux kernel convert scancode to keycode
Keyboard layout convert keycode to symbol/keysym
Linux terminal convert keysym into ASCII sequences

And there are two types of key (see link )

Ordinary key, like "a", "b". we should use them to input text
Special keys, which you would use to tell xterm to perform some action. They could not be to used to input text. They will generate escape sequences.

.inputrc is readline initialization file and used to map key sequence to readline function like "end-of-history". Then you need to use text to describe "special keys" or "escape sequences", see following example.

"\e[1~": beginning-of-line # Home Key
"\e[4~": end-of-line # End Key
"\e[3~": delete-char # Delete Key
"\e\e[C": forward-word # Alt-Right

You could use "showkey -k" or "od -c" to show escape sequence of special keys.

Wayland and weston

Origin link 2023-4-10

Wayland

see overview: Wayland Weston overview
Wayland is a communication protocol that specifies the communication between a display server and its clients, from wikipedia
Weston is the reference implementation of a Wayland compositor, from weston github.

Weston

backends, from "man weston"

drm-backend.so: The DRM backend uses Linux KMS for output and evdev devices for input
wayland-backend.so: The Wayland backend runs on another Wayland server, a different Weston instance
x11-backend.so: The X11 backend runs on an X server
rdp-backend.so: The RDP backend runs in memory without the need of graphical hardware.
to run weston from wsl2, use wayland-backend.so.
to run weston for rdp connection, use rdp-backend.so
all for drm connector, see "/sys/class/drm"

modules/shell

all *.so are located at usr/lib/weston for modules and shell in weston.ini

weston terminal

weston-terminal doesn't display correct Chinese characters with font alias

scale: scale text for high DPI screen

GDK setting for GTK application from application level

export GDK_BACKEND=wayland
#To scale UI elements by an integer only factor
#GTK3/4 does not support fractional scaling currently, so fractional factors will be ignored
export GDK_SCALE=1
#GDK_DPI_SCALE can be used to scale text only
export GDK_DPI_SCALE=1.2

composition level

"[output]" on weston.ini, only work for drm and X11. set "scale=1.5".

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