tdryer

TP-Link Archer A6 Access Point Mode is Broken

Summary

This is a warning about an unresolved issue I discovered when using the [TP-Link Archer A6 v3][Archer A6] (and the similar [Archer A9 V6][Archer A9]) Wi-Fi router in access point mode.

When a Wi-Fi device is connected to the Archer A6 and later roams away to another access point, the roaming device loses connectivity with other devices that are still connected to the Archer A6.

Although TP-Link's technical support was responsive when I emailed them about this issue, they couldn't reproduce it. The best workaround I found was to replace the hardware.

tdryer

How Linux approximates memory metrics

Example

The program threads-memory.c (included below) starts 100 threads, allocates 1 MB of memory in each, and then pauses. How much memory is it using?

Let's find out by running it:

$ gcc -pthread threads-memory.c -o threads-memory

tdryer

Coroutine (mis)use in asyncio and tornado

asyncio

In asyncio, calling a coroutine without scheduling it (using yield from or otherwise) does not run its code.

According to the [asyncio docs]:

Calling a coroutine does not start its code running – the coroutine object

tdryer

Fix for Corsair VOID RGB USB Gaming Headset on Ubuntu 14.04

This headset has two issues on Ubuntu 14.04:

1. Pressing the 'mute' button also causes a middle mouse button click event, which can paste text in X.
2. Spurious button press events are sent (sometimes after pressing the mute button for the first time). Since no corresponding button release event is sent, this causes issues in X with focus getting stuck on the current window.

To fix both issues:

1. Copy the 70-corsair.hwdb file to /etc/udev/hwdb.d/.