WiFi blocked by vc4.ko on kernel 5.10.12 on RPi4B 8GB

Ryutaroh Matsumoto ryutaroh at ict.e.titech.ac.jp
Tue Feb 2 02:20:14 EST 2021

Hi the upstream kernel users on RPi!

With kernel version 5.10.12, WiFi does not work on my RaspberryPi 4B 8GB model.
WiFi starts working if module_blacklist=vc4 is given to the kernel command line,
or the screen is blanked out by the gdm3 display manager after waiting several

With vc4.ko enabled, after touching a mouse and gdm3 login window is displayed,
the WiFi again stops working.

vc4.ko somehow seems to interfere with RPi4B WiFi...

As vc4.ko was unavailable with 5.9 kernel, I did not observe this symptom on 5.9.

I wonder if the above symptom is also observed by other RPi users...

I observe this with vanilla 5.10.12 as well as the Debian kernel as

Best regards, Ryutaroh Matsumoto

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