Missing USB ports with realtime kernel on pi4 4gb

Patchbox OS
1

I’m experiencing a problem that is similar to the one outlined here, although I am using a 4gb raspberry pi 4.

I have been running a 2018 pisound on a pi3 with the old patchbox OS. Then I have run the same setup on a pi4 using raspbian lite, and i have not had any issue with USBs. I decided to try the pi4 with the latest patchbox, flashed the card and then plugged in a novation launchpad, which the pi did not recognise, giving the flashing lights that signify it is powered but not connected.

I initially installed from the 2020-03-14 image, but then I ran sudo apt update and sudo apt upgrade, (which should mean I am running on the equivalent of the 2020-11-23 image?)

I swapped out the SD card back to the raspbian OS and the same setup worked perfectly, so i’m clear it isn’t the hardware.

When I run lsusb on the patchbox os I get the following output:

patch@patchbox  ~  lsusb               
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

This led me to the pi4 8gb thread, and I then did the recommended installation of the non-realtime kernel, and the usbs worked. With the non rt kernel the lsusb output looks like:

patch@patchbox  ~  lsusb
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 002: ID 2109:3431 VIA Labs, Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

I would prefer to be using the rt kernel, but if i don’t have usbs, then it’s a no-go. Does anyone have any other thoughts on what I could do for this?

3

Hmm, this is the first report about USB not working 4GB Pi. Do any other USB devices have issues?

Is there something specific to Novation Launchpad USB implementation? Maybe it requires some newer kernel version or it’s missing some module on the RT kernel. Note that it is an older version compared to what’s available on regular Raspbian kernel. The RT branch was not yet updated to match it.

4

yeah its nothing on the usbs at all. I’m gonna give it another go with the november image from the start and hope that helps

5

Reflashing with the november image has worked - lsusb shows the correct output now.

1 Like
6

I just done an update to the system and now no usb’s. I assume that something got updated and now no usb. I have spend some time setting up to do it again mmm… It would be better if the problem can get solved. If I have to flash an older version does this mean I can’t update and how do I obtain this November image.

7

I have 2 raspi 4 1 running raspi os and the other patchbox osboth updated the same time they look similar updates. raspi os fine patchbox os no usb

8

I would strongly recommend reflashing using the november beta version of patchbox, and see if your USB troubles aren’t fixed then.

1 Like
9

I am having similar issues running the November beta on my 4GB Pi4. Switching away from the RT kernel fixed it. I don’t have a pisound (yet) so I’m just running Patchbox OS without anything plugged in except a mouse and keyboard. I’ll switch to the RT kernel and see if it’s still doing it.

Edit: Yup.

lsusb with RT Kernel :

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

lsusb with non RT Kernel:

Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 005: ID 093a:2510 Pixart Imaging, Inc. Optical Mouse
Bus 001 Device 004: ID 04d9:0006 Holtek Semiconductor, Inc. 
Bus 001 Device 003: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
Bus 001 Device 002: ID 2109:3431 VIA Labs, Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

I seem to remember it worked ok after the first boot but killed it after running a sudo apt upgrade.

10

I have tried November image work for me as well just have to reinstall thank you

11

I have had the same problem with a Rpi 4 4Gb using PatchOS for Modep: after an upgrade earlier this month, I ended up with no USB devices recognised (lsusb just showed the same one line as @risktoparkrageram above). Using dmesg, I could see that the USB devices were recognised during boot time, it’s just that after boot, they were not available

Not willing to reinstall, I have found the following page describing the same problem: Raspberry Pi 4 4Gb modems : USB ports don’t work on ubuntu 19-10. I have updated /boot/config.txt with the text total_mem=3072 right at the end, and rebooted.

While /proc/meminfo/ only shows 3 Gb of RAM for now, at least all my USB devices are showing up.

This may be a useful alternative for those who like do not want to reinstall from scratch.

3 Likes
12

Just had the same problem with a Pi 4 2GB, using the November image.
Steps:

  • Boot using November image
  • Run patchbox wizard, select option to setup RT kernel
  • Reboot, no USB

When I switched back to the regular kernel, USB came back.

13

Is there a solution for Pi 4B 4 GB model yet? Also not seeing connected USB devices (specifically a MIDI controller).

$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

$ cat /proc/cpuinfo
Model		: Raspberry Pi 4 Model B Rev 1.4

I flashed Patchbox OS from 2020-11-23 and switched to the realtime kernel.

14

I am having the same issue with a Pi 4B 4gb!
I tried to add to /boot/config.txt the total_mem=3072 with no luck!

I had to switch back to regular kernel unfortunatly.

Did anyone find a solution?

b.

15

I found this: Release PREEMPT_RT kernel 5.10.35-rt39 for Raspberry Pi · kdoren/linux · GitHub

Did anyone already try it?