I put some fresh armbian buster image to my cubieboard (1). Although no (real) application was installed, a load of around 20-30% could be seen. First I located the K-worker problem on A20 based boards thread and blacklisted sun4i_gpadc and sun4i_gpadc_iio. But after removing my display and booting the system still there was some kworker load almost stopping the system every 5-10 seconds.

 

Digging deeper I found a description and a possible solution of the problem. Looking a my Olimex A20 Lime2 which I am currently testing with the new olimage by Olimex because of the never solved gigabit problems of my board, the same behaviour could be seen. The modules sun4i_gpadc and sun4i_gpadc_iio were already blacklisted, but the headless system showed the same kworker activity. I tried the suggestion and removed the sun4i_drm_hdmi module and immediately the kworker activity stopped and load went down to almost 0.

 

Unfortunately the stock armbian kernel image configures CONFIG_DRM_SUN4I_HDMI not as module. So I had to build my own kernel with setting CONFIG_DRM_SUN4I to m. Then I could remove the sun4i_drm_hdmi module, too. I saw the expected behaviour: The kworker activities are gone and load went down to almost 0.

 

So my suggestion is to change the stock kernel configuration for CONFIG_DRM_SUN4I to module. Then headless users can blacklist the module sun4i_drm_hdmi and don't need to build their own kernels.

 

15 minutes ago, wahlm said:

So my suggestion is to change the stock kernel configuration for CONFIG_DRM_SUN4I to module. Then headless users can blacklist the module sun4i_drm_hdmi and don't need to build their own kernels.

Great find  

 

This is also a good opportunity to send a small patch with changes to the config to our build system (best to do it for all sunxi configs). Our greatest suffer in this project is a big pile of maintenance tasks and any, even the smallest simple things, take some burden away. Thank you and anyone for implementing it.

 

 

Thanks for the suggestion! I just forked the repo and will provide a PR.