vc4-kms-v3d boot failure focal armhf preinstalled server

[Kyle Nitzsche]

Booting 20.04 armhf preinstalled-server on Pi3b+ with vc4-kms-v3d selected [1] causes boot failure with [2] output on UART. Further system info in [3]

Side note: Booting with the same usercfg.txt but with the 18.04 vc4-kms-v3d.dtbo file "works": the boot is normal without the errors shown in [2].

[1]

ubuntu@ubuntu:~$ cat /boot/firmware/usercfg.txt
# Place "config.txt" changes (dtparam, dtoverlay, disable_overscan, etc.) in
# this file. Please refer to the README file for a description of the various
# configuration files on the boot partition.
dtoverlay=vc4-kms-v3d

[2]

  Starting kernel ...

[ 0.039873] cma: CMA area linux,cma could not be activated
[ 0.043189] DMA: failed to allocate 1024 KiB pool for atomic coherent
allocation
[ 0.308022] kobject_add_internal failed for 3e513000.framebuffer with
-EEXIST, don't try to register things with the s.
[ 1.141370] kvm [1]: Error, CPU 0 not supported!
[ 1.235565] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
GPIO 0 config (-12 80)
[ 1.236723] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
GPIO 1 config (-12 81)
[ 1.237882] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
GPIO 2 config (-12 82)
[ 1.239014] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
GPIO 3 config (-12 83)
[ 1.240139] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
GPIO 4 config (-12 84)
[ 1.241263] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
GPIO 5 config (-12 85)
[ 1.242412] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
GPIO 6 config (-12 86)
[ 1.243526] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
GPIO 7 config (-12 87)
[ 1.831440] spi-bcm2835 3f204000.spi: could not get clk: -517
[ 1.849256] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
GPIO 2 config (-12 82)
[ 1.850523] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
GPIO 2 config (-12 82)
[ 1.852205] bcm2835_vchiq 3f00b840.mailbox: could not allocate DMA memory
[ 2.369653] spi-bcm2835 3f204000.spi: cannot prepare fill_tx_desc -
not using DMA mode
[ 2.412710] sdhost: failed to allocate log buf
ext4

[3]

ubuntu@ubuntu:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04.1 LTS
Release: 20.04
Codename: focal

ubuntu@ubuntu:~$ uname -a
Linux ubuntu 5.4.0-1015-raspi #15-Ubuntu SMP Fri Jul 10 05:37:25 UTC 2020 armv7l armv7l armv7l GNU/Linux

Initial part of lshw:
ubuntu
    description: ARMv7 Processor rev 4 (v7l)
    product: Raspberry Pi 3 Model B Plus Rev 1.3
    serial: 0000000092021ecd
    width: 32 bits
    capabilities: smp

[Jon Watson (jwatson-kdp)]

I was able to confirm that if I started from a clean install of Ubuntu 20.04 I could copy the 18.04 .dtbo file per the workaround described above and get the board to boot with the usercfg.txt / dtoverlay=vc4-kms-v3d setting in place.

I was unable to make it work on my initial install, which I had been using for about a week.

[Kyle Nitzsche (knitzsche)]

Project noticed this frame buffer "failed" message in boot console and we are not sure if it is problem or not:

Starting kernel ...

[ 0.313431] kobject_add_internal failed for 3e812000.framebuffer with -EEXIST, don't try to register things with the same name in the same directory.

[ 1.160342] kvm [1]: Error, CPU 0 not supported!

[ 1.831690] spi-bcm2835 3f204000.spi: could not get clk: -517

[ 4.365423] debugfs: Directory '3f902000.hdmi' with parent 'vc4-hdmi' already present!

ext4

Thu Jan 1 00:00:06 UTC 1970

[Juerg Haefliger (juergh)]

The above are benign warnings that should actually be suppressed.

I confirmed the issue: Fails on armhf, works on arm64.

[Juerg Haefliger (juergh)]

Using 256MB for CMA seems problematic for the armhf kernel. A work-around is to lower it like so:

dtoverlay=vc4-kms-v3d,cma-64

[Jon Watson (jwatson-kdp)]

I will test that with the default .dtbo file and see if it works for us.

[Juerg Haefliger (juergh)]

From my testing cma-128 is the largest that worked.

[Jon Watson (jwatson-kdp)]

OK, we will try CMA-128.... not sure if it will matter for our application since we aren't doing complex 3D rendering.

[Jon Watson (jwatson-kdp)]

Qt responded and thinks cma-128 will work for our application.

I modified our Pi test unit to use the original Ubuntu 20.04 .dtbo file and booted successfully when I used the dtoverlay=vc4-kms-v3d,cma-64 setting.

I will test our UI with this configuration early next week.

[Kyle Nitzsche (knitzsche)]

Hi, a fix for this is needed for an important project. Can we please get a sense of the expected time frame for the fix landing?

[Juerg Haefliger (juergh)]

What fix? The fix is to limit the cma size as indicated in the previous comments.

[Kyle Nitzsche (knitzsche)]

OK, so you are saying it is really not a kernel fix but is rather an enablement file change/config. thanks.

[Jon Watson (jwatson-kdp)]

How is it not a bug when the kernel fails to boot when you use the default setting?

There is a workaround for this problem which is to limit memory, but there is still a crash. The Raspbian kernel doesn't crash -- it works. That would suggest there is a problem here.

JW

-----Original Message-----
From: <email address hidden> <email address hidden> On Behalf Of Kyle Nitzsche
Sent: Friday, September 25, 2020 2:54 PM
To: Jonathan Watson <email address hidden>
Subject: [Bug 1889223] Re: vc4-kms-v3d boot failure focal armhf preinstalled server

- - - external message, proceed with caution - - -

OK, so you are saying it is really not a kernel fix but is rather an enablement file change/config. thanks.

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Title:
  vc4-kms-v3d boot failure focal armhf preinstalled server

Status in linux-raspi package in Ubuntu:
  Invalid
Status in linux-raspi source package in Focal:
  Triaged

Bug description:
  Booting 20.04 armhf preinstalled-server on Pi3b+ with vc4-kms-v3d
  selected [1] causes boot failure with [2] output on UART. Further
  system info in [3]

  Side note: Booting with the same usercfg.txt but with the 18.04 vc4
  -kms-v3d.dtbo file "works": the boot is normal without the errors
  shown in [2].

  [1]

  ubuntu@ubuntu:~$ cat /boot/firmware/usercfg.txt
  # Place "config.txt" changes (dtparam, dtoverlay, disable_overscan, etc.) in
  # this file. Please refer to the README file for a description of the various
  # configuration files on the boot partition.
  dtoverlay=vc4-kms-v3d

  [2]

    Starting kernel ...

  [ 0.039873] cma: CMA area linux,cma could not be activated
  [ 0.043189] DMA: failed to allocate 1024 KiB pool for atomic coherent
  allocation
  [ 0.308022] kobject_add_internal failed for 3e513000.framebuffer with
  -EEXIST, don't try to register things with the s.
  [ 1.141370] kvm [1]: Error, CPU 0 not supported!
  [ 1.235565] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
  GPIO 0 config (-12 80)
  [ 1.236723] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
  GPIO 1 config (-12 81)
  [ 1.237882] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
  GPIO 2 config (-12 82)
  [ 1.239014] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
  GPIO 3 config (-12 83)
  [ 1.240139] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
  GPIO 4 config (-12 84)
  [ 1.241263] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
  GPIO 5 config (-12 85)
  [ 1.242412] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
  GPIO 6 config (-12 86)
  [ 1.243526] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
  GPIO 7 config (-12 87)
  [ 1.831440] spi-bcm2835 3f204000.spi: could not get clk: -517
  [ 1.849256] raspberrypi-exp-gpio soc:firmware:expgpio: Failed to get
  GPIO 2 config (-12 82)
  [ 1.850523] raspberrypi-exp-gpio soc:firmware:expgpio: ...

[Kyle Nitzsche (knitzsche)]

@Juerg,

Is it correct that all that is required to make v3d driver work on armhf pi3+b is to modify the /boot/firmware/usercfg.txt to include:

dtoverlay=vc4-kms-v3d,cma-64,cma-128

@Jon,

Note that the pi-gadget default uses fkms, not kms. For example the 18 armhf:
https://github.com/snapcore/pi-gadget/blob/18-arm64/configs/core/config.txt.armhf#L19

Which works. If one wants to use vc4-kms-v3d, then that's a modification, and it works if you modify it correctly as shown above.

[Juerg Haefliger (juergh)]

Documented work-around so closing as 'Fix Released'. Please open a new bug report if you still encounter the problem.