Linux-6.9.4 vboxdrv breaks detection of screen resoltuion for some Intel graphic chips

[David C Rankin]

  OS      : Archlinux
  Kernel  : 6.9.4
  Install : VirtualBox-7.0.18-162988-Linux_amd64.run

This bug was originally filed as a kernel bug after Archlinux released the 6.9.4 kernel. See "linux-6.9.4 monitor type/size detection fails for Dell box (6.9.3 is fine)" ​https://gitlab.archlinux.org/archlinux/packaging/packages/linux/-/issues/62

The Dell Optiplex 360 at issue had run virtualbox and Archlinux since Jan. 8, 2017 and through all kernels and had properly detected the Samsung 59" TV at the correct 1920x1080 for both console and X resolutions. (it serves as a media center). Upon update to linux-6.9.4 (from 6.9.3) it no longer detects the proper resolution, instead setting an unusable 1024x768 default.

Troubleshooting the Arch bug, the virtualbox modules were blacklisted to remove the kernel taint before starting a bisection. Blacklisting the virtualbox PUEL 7.18.0 modules resolved the problem allowing proper detection of screen resolution with the 6.9.4 kernel. (the problem appears to be a regression somewhere)

Since the problem was eliminated by blacklisting the virtualbox driver and removing the kernel taint, the decision was made to close the kernel bug and open the issue here.

The attached files below are the dmesg output for both kernel 6.9.3 and 6.9.4 with the virtualbox modules present in dmesg-linux-6.9.3-and-6.9.4.tar.zst (tarred and zstd compressed) and the dmesg output for linux-6.9.4 with the modules blacklisted. (dmesg-6.9.4-vbox-blacklist.zst zstd compressed) Other than showing the kernel taint removed, they are not that instructive.

The salient entries appear in the Xorg.0.log files. Attached as Xorg.0.log-6.9.3-and-6.9.4.tar.zst (tarred and zstd compressed). With 6.9.3, everything is fine:

  [  1035.029] (--) intel(0): Integrated Graphics Chipset: Intel(R) G33
  [  1035.029] (--) intel(0): CPU: x86-64, sse2, sse3, ssse3, sse4.1; using a maximum of 2 threads
  [  1035.029] (II) intel(0): Creating default Display subsection in Screen section
          "Default Screen Section" for depth/fbbpp 24/32
  [  1035.029] (==) intel(0): Depth 24, (--) framebuffer bpp 32
  [  1035.029] (==) intel(0): RGB weight 888
  [  1035.029] (==) intel(0): Default visual is TrueColor
  [  1035.029] (II) intel(0): Output VGA1 has no monitor section
  [  1035.030] (II) intel(0): Enabled output VGA1
  [  1035.030] (--) intel(0): Using a maximum size of 256x256 for hardware cursors
  [  1035.030] (II) intel(0): Output VIRTUAL1 has no monitor section
  [  1035.030] (II) intel(0): Enabled output VIRTUAL1
  [  1035.030] (--) intel(0): Output VGA1 using initial mode 1920x1080 on pipe 0
  ...
  [  1035.285] (II) intel(0): switch to mode 1920x1080@60.0 on VGA1 using pipe 0, position (0, 0), rotation normal, reflection none
  [  1035.296] (II) intel(0): Setting screen physical size to 508 x 285

With 6.9.4, the resolution drops to default 1024x768, e.g.

  [  5371.539] (--) intel(0): Output VGA1 using initial mode 1024x768 on pipe 0
  ...
  [  5371.571] (II) intel(0): switch to mode 1024x768@75.0 on VGA1 using pipe 0, position (0, 0), rotation normal, reflection none
  [  5371.576] (II) intel(0): Setting screen physical size to 270 x 203

Removing the virtualbox driver allows proper 1920x1080 detection again, so something has changed in how the virtualbox driver is handled by the kernel or vice-versa in 6.9.4.

Let me know what other information you would like and I'll happily provide it. I'm not sure where to go next troubleshooting this issue.

[David C Rankin]

dmesg files for linux-6.9.3 and 6.9.4 with vboxdrv loaded

[David C Rankin]

dmesg output for 6.9.4 kernel with vboxdrv blacklisted

[David C Rankin]

Xorg.0.log files for 6.9.3 and 6.9.4 kernels showing difference in resolution detected with vboxdrv loaded