PSA: WiFi driver is broken - Unload kernel module to save lots of power

[Trbl]

120-170+mA of savings.

rfkill / iface down does not work properly, the wifi module will consume more power when disabled than when enabled. Toggling WiFi off does cause more powerdraw than leaving it on.

PHP Code:

sudo rmmod 8723cs    # kill wifi
sudo modprobe 8723cs # restore wifi 


Megi reproduced my findings today and is aware of the issue.

hmm, right, I can measure 416mA when wlan0 is up, and 505 mA when down, and 380mA when the driver is unloaded

Unloading the kernel module is currently the only workaround.

Maybe let the maintainers of the distro you're using know - I've already notified the SXMO team.

[dcinoz]

Do you know which kernel version(s) are affected? Presumably a kernel downgrade is another option?
I'm using Manjaro Phosh Beta 11 and I noticed the battery drain before reading this and was wondering what was happening.

[Trbl]

Do you know which kernel version(s) are affected? Presumably a kernel downgrade is another option?
I'm using Manjaro Phosh Beta 11 and I noticed the battery drain before reading this and was wondering what was happening.

Probably since 5.10, I know it's an issue on 5.12 for fact, but that driver was put into the 5.10 kernel initially according to megi's blog.

[Merc]

I can confirm this bug for sure.

Wi-Fi off (rmmod): 1.45 W
Wi-Fi on (and connected to AP): 1.55W
Wi-Fi "off" : 1.85 W

Code:

linux-pine64 5.12.7-1
phosh 0.11.0-1

This is good to know, I turn my Wi-Fi off when I go to sleep, this should save me some battery LOL.