/dev/media0 missing

jgauthier · October 13, 2020

Greetings,

Some time ago, I built armbian with kernel 5.4.51. I applied a patch to two dts files that allowed for the OV5640 camera to work. By "work", I mean /dev/video0 was present in the system and /dev/media0 was also present. I could set camera parameters with media-ctl pointing to /dev/media0.

Now, I've updated, and using a legacy kernel, 5.4.65, I cannot reproduce this. I've applied the same dts changes, but upon booting this image /dev/media0 is missing.

I've compared the two kernel configurations, and there are very minimal differences:

# diff config-5.4.51-sunxi /boot/config-5.4.65-sunxi
3c3
< # Linux/arm 5.4.51 Kernel Configuration
---
> # Linux/arm 5.4.65 Kernel Configuration
2116d2115
< # CONFIG_BLK_DEV_SR_VENDOR is not set
2644a2644
> # CONFIG_RTL8192EU is not set
3165a3166
> CONFIG_SPI_DYNAMIC=y

likewise, comparing loaded modules shows me that on my 5.4.65 build ov5640 is not in use:

Module                  Size  Used by
ov5640                 28672  0

On my 5.4.51 build, it is in use.

I'm not sure where to go from here.

Werner · October 13, 2020

https://github.com/armbian/build/commits/master/patch/kernel/sunxi-legacy

Although there do not seem to be any significant changes over the last month or so feel free to start digging there.

Also providing armbianmonitor -u anyways is a good idea in general and best practice when opening an issue complaint

jgauthier · October 13, 2020

Thanks. In the few times I tried to run armbianmonitor -u, it would not return an url. It did this time though.

http://ix.io/2ADz

I'll check those patches. With my limited understanding of what creates /dev/media0. I wonder if something I've done in the DTB definition has caused it's lack of creation.