Ubuntu
linux-raspi package

"kernel: vc4-drm gpu: swiotlb buffer is full" messages when connected to a gnome-remote-desktop session in wayland

Bug #1978051 reported by fprietog
22
This bug affects 4 people
Affects Status Importance Assigned to Milestone
linux-raspi (Ubuntu)
Triaged
Undecided
Unassigned

Bug Description

Problem summary:
----------------
System is a Raspberry Pi 4 Model B Rev 1.4 (8Gb)

While you are connected to a gnome-remote-desktop session in Wayland (using either RDP or VNC backends) the system log is populated with these kind of messages several times per second:

...
jun 08 10:13:08 fpgrpi kernel: vc4-drm gpu: swiotlb buffer is full (sz: 4194304 bytes), total 32768 (slots), used 14 (slots)
jun 08 10:13:08 fpgrpi kernel: vc4-drm gpu: swiotlb buffer is full (sz: 4194304 bytes), total 32768 (slots), used 106 (slots)
jun 08 10:13:08 fpgrpi kernel: vc4-drm gpu: swiotlb buffer is full (sz: 8294400 bytes), total 32768 (slots), used 2 (slots)
jun 08 10:13:08 fpgrpi kernel: vc4-drm gpu: swiotlb buffer is full (sz: 8294400 bytes), total 32768 (slots), used 2 (slots)
jun 08 10:13:08 fpgrpi kernel: vc4-drm gpu: swiotlb buffer is full (sz: 8294400 bytes), total 32768 (slots), used 2 (slots)
jun 08 10:13:08 fpgrpi kernel: vc4-drm gpu: swiotlb buffer is full (sz: 8294400 bytes), total 32768 (slots), used 2 (slots)
jun 08 10:13:09 fpgrpi kernel: vc4-drm gpu: swiotlb buffer is full (sz: 1933312 bytes), total 32768 (slots), used 2 (slots)
jun 08 10:13:09 fpgrpi kernel: vc4-drm gpu: swiotlb buffer is full (sz: 4194304 bytes), total 32768 (slots), used 14 (slots)
jun 08 10:13:09 fpgrpi kernel: vc4-drm gpu: swiotlb buffer is full (sz: 4194304 bytes), total 32768 (slots), used 106 (slots)
jun 08 10:13:09 fpgrpi kernel: vc4-drm gpu: swiotlb buffer is full (sz: 8294400 bytes), total 32768 (slots), used 2 (slots)
jun 08 10:13:13 fpgrpi kernel: swiotlb_tbl_map_single: 82 callbacks suppressed
...

The gnome-remote-desktop session works as expected but performance is degraded.

These messages stops when you disconnect to gnome-remote-desktop session.

While you are connected to a gnome-remote-desktop session under X11 there are no messages at all and performance is better. So it seems to be a Wayland only problem.

How to reproduce:
-----------------
Connect to a gnome-remote-session under Wayland (it doesn't care if you connect to RDP or VNC backend). These messages will start to populate system log immediately.

Aditional info:
---------------
# lsb_release -rd
Description: Ubuntu 22.04 LTS
Release: 22.04

#uname -a
Linux fpgrpi 5.15.0-1011-raspi #13-Ubuntu SMP PREEMPT Thu Jun 2 11:44:34 UTC 2022 aarch64 aarch64 aarch64 GNU/Linux

#apt-cache policy gnome-remote-desktop
gnome-remote-desktop:
  Instalados: 42.1.1-0ubuntu1
  Candidato: 42.1.1-0ubuntu1
  Tabla de versión:
 *** 42.1.1-0ubuntu1 500
        500 http://ports.ubuntu.com/ubuntu-ports jammy-updates/main arm64 Packages
        100 /var/lib/dpkg/status

Tags: kern-3493
Juerg Haefliger (juergh)
tags: added: kern-3493
Juerg Haefliger (juergh)
Changed in linux-raspi (Ubuntu):
status: New → Triaged
Revision history for this message
Geijer (geijer) wrote :

$ lsb_release -rd
Description: Ubuntu 22.04.1 LTS
Release: 22.04
$ uname -a
Linux minime 5.15.0-1013-raspi #15-Ubuntu SMP PREEMPT Mon Aug 8 06:33:06 UTC 2022 aarch64 aarch64 aarch64 GNU/Linux
$ apt-cache policy gnome-remote-desktop
gnome-remote-desktop:
  Installed: 42.3-0ubuntu1
  Candidate: 42.3-0ubuntu1
  Version table:
 *** 42.3-0ubuntu1 500
        500 http://ports.ubuntu.com/ubuntu-ports jammy-updates/main arm64 Packages
        100 /var/lib/dpkg/status
     42.0-4ubuntu1 500
        500 http://ports.ubuntu.com/ubuntu-ports jammy/main arm64 Packages

Excerpt from log:
Sep 5 08:13:29 minime kernel: [ 3200.341586] vc4-drm gpu: swiotlb buffer is full (sz: 5742592 bytes), total 32768 (slots), used 2827 (slots)
Sep 5 08:13:29 minime kernel: [ 3200.641396] vc4-drm gpu: swiotlb buffer is full (sz: 524288 bytes), total 32768 (slots), used 2843 (slots)
Sep 5 08:13:29 minime kernel: [ 3200.690931] vc4-drm gpu: swiotlb buffer is full (sz: 1085440 bytes), total 32768 (slots), used 2817 (slots)
Sep 5 08:13:29 minime kernel: [ 3200.741449] vc4-drm gpu: swiotlb buffer is full (sz: 5742592 bytes), total 32768 (slots), used 2827 (slots)
Sep 5 08:13:30 minime kernel: [ 3201.041753] vc4-drm gpu: swiotlb buffer is full (sz: 524288 bytes), total 32768 (slots), used 2843 (slots)
Sep 5 08:13:30 minime kernel: [ 3201.090669] vc4-drm gpu: swiotlb buffer is full (sz: 1085440 bytes), total 32768 (slots), used 2817 (slots)
Sep 5 08:13:30 minime kernel: [ 3201.639811] vc4-drm gpu: swiotlb buffer is full (sz: 524288 bytes), total 32768 (slots), used 2843 (slots)
Sep 5 08:13:31 minime kernel: [ 3201.780130] vc4-drm gpu: swiotlb buffer is full (sz: 5742592 bytes), total 32768 (slots), used 2827 (slots)
Sep 5 08:13:51 minime kernel: [ 3222.454510] vc4-drm gpu: swiotlb buffer is full (sz: 524288 bytes), total 32768 (slots), used 2843 (slots)
Sep 5 08:14:00 minime kernel: [ 3230.788604] vc4-drm gpu: swiotlb buffer is full (sz: 1085440 bytes), total 32768 (slots), used 2817 (slots)
Sep 5 08:14:21 minime kernel: [ 3252.600876] vc4-drm gpu: swiotlb buffer is full (sz: 5742592 bytes), total 32768 (slots), used 2827 (slots)
Sep 5 08:16:21 minime kernel: [ 3372.521875] vc4-drm gpu: swiotlb buffer is full (sz: 524288 bytes), total 32768 (slots), used 2843 (slots)
Sep 5 08:16:51 minime kernel: [ 3402.558505] vc4-drm gpu: swiotlb buffer is full (sz: 1085440 bytes), total 32768 (slots), used 2817 (slots)
Sep 5 08:17:00 minime kernel: [ 3410.815290] vc4-drm gpu: swiotlb buffer is full (sz: 5742592 bytes), total 32768 (slots), used 2827 (slots)

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

https://<email address hidden>/

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