This is approach 3, version 2, of my patch series to sort out Xorg autoconfiguration for the Hibmc card beind a Hisilicon bridge on arm64. Approach 1 was a simple quirk for the card+bridge to mark it as default. This higlighted the fact that the default card was picked by the arbiter, which assumed legacy resources. The lack of legacy resources leads to quirks in ppc and concerns in arm land, so a more generic approach was desired. Link: https://www.spinics.net/lists/linux-pci/msg62865.html Approach 2 allowed platforms to opt in to a class enable hook that added a card as default if there was no default. This: - was possibly racy as ACPI PCI init and vgaarb are both subsys initcalls. - didn't check to see if a card had a driver. - meant that platforms for which the vga arbiter didn't make sense still needed it. Links: https://www.spinics.net/lists/linux-pci/msg63092.html https://www.spinics.net/lists/linux-pci/msg63083.html This is approach 3. It pulls the default handling out of the arbiter, into its own file and behind its own Kconfig option. It adds the extra detection as a late initcall and an enable hook that only operates after the initcall, so it's not racy. It checks for drivers. It means people can turn off the vga arbiter. It works sensibly for modules too. v1: https://www.spinics.net/lists/linux-pci/msg63581.html Changes in v2: Drop all the powerpc patches. Including just the new handler doesn't change behaviour on powerpc. This is because - as Bjorn pointed out on v1 - I had not fully understood how fixup_vga worked. fixup_vga is quite aggressive: if there is no default, and it finds a VGA card, it will mark that card as default. Later on, if it finds a card with decoding enabled, it will update the default. This means that if there is any vga card in the system at all, a default will be marked. This all happens at the FIXUP_CLASS_FINAL stage, so if there is a vga card, a default will be marked before the late_initcall that kicks off this new discovery process. This will completely prevent my code from firing. Once this is merged I will discuss with the ppc folks if they want to move to this approach or if ppc should continue to be very optimistic about the cards it marks as default. Regards, Daniel Daniel Axtens (1): Split VGA default device handler out of VGA arbiter arch/ia64/pci/fixup.c | 2 +- arch/powerpc/kernel/pci-common.c | 2 +- arch/x86/pci/fixup.c | 2 +- arch/x86/video/fbdev.c | 2 +- drivers/gpu/vga/Kconfig | 12 +++ drivers/gpu/vga/Makefile | 1 + drivers/gpu/vga/vga_default.c | 159 +++++++++++++++++++++++++++++++++++++++ drivers/gpu/vga/vga_switcheroo.c | 2 +- drivers/gpu/vga/vgaarb.c | 41 +--------- drivers/pci/pci-sysfs.c | 2 +- include/linux/vga_default.h | 44 +++++++++++ include/linux/vgaarb.h | 14 ---- 12 files changed, 225 insertions(+), 58 deletions(-) create mode 100644 drivers/gpu/vga/vga_default.c create mode 100644 include/linux/vga_default.h -- 2.11.0 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
