linux-kernel - [PATCH v3 0/7] Adjust fbcon console device detection

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Message-ID: <20250620024943.3415685-1-superm1@kernel.org>
Date: Thu, 19 Jun 2025 21:49:36 -0500
From: Mario Limonciello <superm1@...nel.org>
To: Bjorn Helgaas <bhelgaas@...gle.com>
Cc: Alex Deucher <alexander.deucher@....com>,
	Christian König <christian.koenig@....com>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	Lukas Wunner <lukas@...ner.de>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Woodhouse <dwmw2@...radead.org>,
	Lu Baolu <baolu.lu@...ux.intel.com>,
	Joerg Roedel <joro@...tes.org>,
	Will Deacon <will@...nel.org>,
	Robin Murphy <robin.murphy@....com>,
	Alex Williamson <alex.williamson@...hat.com>,
	Jaroslav Kysela <perex@...ex.cz>,
	Takashi Iwai <tiwai@...e.com>,
	dri-devel@...ts.freedesktop.org (open list:DRM DRIVERS),
	linux-kernel@...r.kernel.org (open list),
	iommu@...ts.linux.dev (open list:INTEL IOMMU (VT-d)),
	linux-pci@...r.kernel.org (open list:PCI SUBSYSTEM),
	kvm@...r.kernel.org (open list:VFIO DRIVER),
	linux-sound@...r.kernel.org (open list:SOUND),
	Daniel Dadap <ddadap@...dia.com>,
	Mario Limonciello <mario.limonciello@....com>
Subject: [PATCH v3 0/7] Adjust fbcon console device detection

From: Mario Limonciello <mario.limonciello@....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 to fbcon, fall back to VGA arbiter.

In order for userspace to also be able to discover which device was the
primary framebuffer create a link to that device from fbcon.

v2->v3:
 * Pick up tags
 * Drop old patch 6
 * Add 2 new patches for fbcon

Link: https://lore.kernel.org/linux-pci/20250617175910.1640546-1-superm1@kernel.org/ [1]

Mario Limonciello (7):
  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()
  PCI/VGA: Move check for firmware default out of VGA arbiter
  fbcon: Make a symlink to the device selected as primary

 arch/x86/video/video-common.c    | 28 +++++++++++++++++++++++++
 drivers/gpu/vga/vga_switcheroo.c |  2 +-
 drivers/iommu/intel/iommu.c      |  2 +-
 drivers/pci/vgaarb.c             | 36 ++------------------------------
 drivers/vfio/pci/vfio_pci_igd.c  |  3 +--
 drivers/video/fbdev/core/fbcon.c | 10 ++++++++-
 include/linux/pci.h              | 15 +++++++++++++
 sound/hda/hdac_i915.c            |  2 +-
 sound/pci/hda/hda_intel.c        |  4 ++--
 9 files changed, 60 insertions(+), 42 deletions(-)

-- 
2.43.0