Ubuntu
linux-raspi2 package

/dev/vcsm-cma missing on Ubuntu 18.04.4 aarch64

Bug #1867428 reported by ahb
8
This bug affects 1 person
Affects Status Importance Assigned to Milestone
linux-raspi2 (Ubuntu)
New
Undecided
Unassigned
Bionic
Fix Released
Undecided
Unassigned

Bug Description

On fully upgraded Ubuntu 18.04 aarch64 the vc_sm_cma kernel module does not expose /dev/vcsm-cma, thus application working with the Raspberry Pi Camera, e.g. raspivid, do not work properly.

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.4 LTS
Release: 18.04
Codename: bionic

Test with both linux-image-5.3.0-1017-raspi2 and linux-image-5.3.0-1018-raspi2 in combination with with https://github.com/raspberrypi/userland at 6e6a2c859a17a195fbb6a97c9da584dd2b9b0178 compiled using ./buildme --aarch64 on Raspberry Pi 4 and 3+.

Everything works, if I use a recent Raspbian kernel on the Ubuntu image:
Copy RASPBIAN/boot/kernel8.img to UBUNTU/boot/firmware/vmlinuz, RASPBIAN/boot/bcm2711-rpi-4-b.dtb to UBUNTU/boot/firmware/ and RASPBIAN/lib/modules/4.19.97-v8+ to UBUNTU/lib/modules.

I cannot tell whether the problem is specific to the 5.3.0 kernel compiled for Ubuntu or a general issue with the 5.3.0 kernel as the Raspbian kernel is still based on 4.19.

Revision history for this message
Juerg Haefliger (juergh) wrote :

Can you try a Focal image from http://cdimage.ubuntu.com/ubuntu-server/daily-preinstalled/current/
while I'm debugging this on Bionic?

I do see /dev/vcsm-cma on Focal with the 5.4.0-1006.6 kernel.

Revision history for this message
ahb (andreas-bihlmaier) wrote :

Using the daily focal image (2020-03-30) with identical raspberrypi/userland everything works "out of the box":

# uname -a
Linux ubuntu 5.4.0-1006-raspi2 #6-Ubuntu SMP Mon Mar 16 13:08:46 UTC 2020 aarch64 aarch64 aarch64 GNU/Linux
# /opt/vc/bin/vcgencmd get_camera
supported=1 detected=1
# /opt/vc/bin/raspistill -o test.jpg
# ll /dev/vcsm-cma
crw-rw-rw- 1 root root 10, 60 Mar 18 19:32 /dev/vcsm-cma

Only changes to image were:
- installing build-essential and cmake
- enabling the camera (adding start_x=1 gpu_mem=128 to /boot/firmware/config.txt (Note: It did not work adding these to /boot/firmware/usercfg.txt))
- compiling userland

Revision history for this message
Juerg Haefliger (juergh) wrote :

@ahb can you verify that this works now with a recent bionic image? Bionic is using the 5.4 kernel now.

Revision history for this message
Juerg Haefliger (juergh) wrote :

Newer Bionic images now use the 5.4 kernel which should fix this problem. Therefore closing the ticket. Please open a new one if you still experience problems.

Changed in linux-raspi2 (Ubuntu Bionic):
status: New → Fix Released
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