shengliangd's blog

Problems are inevitable.
Problems are solvable.

Backport a USB WiFi 6 Driver in Linux Kernel

This blog introduces how to backport a driver (mt7921u) for a USB WiFi 6 adapter from Linux 5.19 to Linux 5.10 (finally got ~600Mbps with a WiFi 6 router). The motivation was described in my previo...

Posted by shengliangd's blog on January 1, 2023

WiFi 6 on Jetson Xavier NX

I want to use a WiFi 6 USB adapter (CF-953AX) on Jetson Xavier NX. This is quite tricky because the kernel driver (mt7921u) is available only after Linux 5.19, while the newest Jetson SDK comes wit...

Posted by shengliangd's blog on December 30, 2022

We Do Not Know We Know——《无穷的开始》读后感

从找规律填数说起想必读者曾经做过“找规律填数”的题目，例如：3, 5, 9, 15, 23, __, __ 。想到正确答案应该不难：3+2=5，5+4=9，9+6=15，15+8=23，23+10=33，33+12=45。写个递推公式：$a_1=3, a_i=a_{i-1}+2(i-1)$。但为什么不能是别的答案？小时候做这种题的时候，特别是想不出合适的答案的时候，我就会开始想一些奇奇怪...

Posted by shengliangd's blog on March 6, 2022

一些有趣的科幻短篇

小心，轻度剧透！《山》——刘慈欣一个诞生于岩石星球内部的硅基文明将如何逐渐解开关于这个宇宙的奥秘？《你一生的故事》——特德$\cdot{}$姜费马原理：光传播的路径是光程取极值的路径。 “你习惯于从因果关系的角度考虑光的折射：接触水面是因，产生折射改变方向是果。你之所以觉得费马定理古怪，原因在于它是从目的，以及达成目的的手段这个角度来描述光的。好像有谁向光下了一道圣旨：令尔...

Posted by shengliangd's blog on January 8, 2022

Some Ado about Time between Python and ROS2

Recently I needed synchronized time between a Python program and a piece of code in ROS2. With a little bit of googling I used time.monotonic() in Python and the clock given by rcl_steady_clock_ini...

Posted by shengliangd's blog on January 9, 2021