[PATCH v5 0/9] Adjust fbcon console device detection

Mario Limonciello superm1 at kernel.org
Tue Jun 24 20:30:33 UTC 2025


From: Mario Limonciello <mario.limonciello at amd.com>

This series started out as changes to VGA arbiter to try to handle a case
of a system with 2 GPUs that are not VGA devices [1].  This was discussed
but decided not to overload the VGA arbiter for non VGA devices.

Instead move the x86 specific detection of framebuffer resources into x86
specific code that the fbcon can use to properly identify the primary
device. This code is still called from the VGA arbiter, and the logic does
not change there. To avoid regression default to VGA arbiter and only fall
back to looking up with x86 specific detection method.

In order for userspace to also be able to discover which device was the
primary video display device create a new sysfs file 'boot_display'.

A matching userspace implementation for this file is available here:
https://gitlab.freedesktop.org/xorg/lib/libpciaccess/-/merge_requests/39
https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2038

Mario Limonciello (9):
  PCI: Add helper for checking if a PCI device is a display controller
  vfio/pci: Use pci_is_display()
  vga_switcheroo: Use pci_is_display()
  iommu/vt-d: Use pci_is_display()
  ALSA: hda: Use pci_is_display()
  Fix access to video_is_primary_device() when compiled without
    CONFIG_VIDEO
  PCI/VGA: Replace vga_is_firmware_default() with a screen info check
  fbcon: Use screen info to find primary device
  PCI: Add a new 'boot_display' attribute

 Documentation/ABI/testing/sysfs-bus-pci |  9 ++++++++
 arch/parisc/include/asm/video.h         |  2 +-
 arch/sparc/include/asm/video.h          |  2 ++
 arch/x86/include/asm/video.h            |  2 ++
 arch/x86/video/video-common.c           | 13 ++++++++++-
 drivers/gpu/vga/vga_switcheroo.c        |  2 +-
 drivers/iommu/intel/iommu.c             |  2 +-
 drivers/pci/pci-sysfs.c                 | 14 ++++++++++++
 drivers/pci/vgaarb.c                    | 29 ++-----------------------
 drivers/vfio/pci/vfio_pci_igd.c         |  3 +--
 include/linux/pci.h                     | 15 +++++++++++++
 sound/hda/hdac_i915.c                   |  2 +-
 sound/pci/hda/hda_intel.c               |  4 ++--
 13 files changed, 63 insertions(+), 36 deletions(-)

-- 
2.43.0



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