Hey, Op 31-01-2022 om 23:23 schreef Bjorn Helgaas: > [+to Maarten, Maxime, Thomas; beginning of thread: > https://lore.kernel.org/r/20220106000658.243509-1-helgaas@xxxxxxxxxx] > > On Wed, Jan 05, 2022 at 06:06:48PM -0600, Bjorn Helgaas wrote: >> From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> >> >> Current default VGA device selection fails in some cases because part of it >> is done in the vga_arb_device_init() subsys_initcall, and some arches >> enumerate PCI devices in pcibios_init(), which runs *after* that. > Where are we at with this series? Is there anything I can do to move > it forward? > > Bjorn Hi Bjorn, I'm afraid that I don't understand the vga arbiter or the vga code well enough to review. Could you perhaps find someone who could review? I see Chen wrote some patches and tested, so perhaps they could? ~Maarten >> For example: >> >> - On BMC system, the AST2500 bridge [1a03:1150] does not implement >> PCI_BRIDGE_CTL_VGA. This is perfectly legal but means the legacy VGA >> resources won't reach downstream devices unless they're included in the >> usual bridge windows. >> >> - vga_arb_select_default_device() will set a device below such a bridge >> as the default VGA device as long as it has PCI_COMMAND_IO and >> PCI_COMMAND_MEMORY enabled. >> >> - vga_arbiter_add_pci_device() is called for every VGA device, either at >> boot-time or at hot-add time, and it will also set the device as the >> default VGA device, but ONLY if all bridges leading to it implement >> PCI_BRIDGE_CTL_VGA. >> >> - This difference between vga_arb_select_default_device() and >> vga_arbiter_add_pci_device() means that a device below an AST2500 or >> similar bridge can only be set as the default if it is enumerated >> before vga_arb_device_init(). >> >> - On ACPI-based systems, PCI devices are enumerated by acpi_init(), which >> runs before vga_arb_device_init(). >> >> - On non-ACPI systems, like on MIPS system, they are enumerated by >> pcibios_init(), which typically runs *after* vga_arb_device_init(). >> >> This series consolidates all the default VGA device selection in >> vga_arbiter_add_pci_device(), which is always called after enumerating a >> PCI device. >> >> Almost all the work here is Huacai's. I restructured it a little bit and >> added a few trivial patches on top. >> >> I'd like to move vgaarb.c to drivers/pci eventually, but there's another >> initcall ordering snag that needs to be resolved first, so this leaves >> it where it is. >> >> Bjorn >> >> Version history: >> V0 original implementation as final quirk to set default device. >> https://lore.kernel.org/r/20210514080025.1828197-6-chenhuacai@xxxxxxxxxxx >> >> V1 rework vgaarb to do all default device selection in >> vga_arbiter_add_pci_device(). >> https://lore.kernel.org/r/20210705100503.1120643-1-chenhuacai@xxxxxxxxxxx >> >> V2 move arbiter to PCI subsystem, fix nits. >> https://lore.kernel.org/r/20210722212920.347118-1-helgaas@xxxxxxxxxx >> >> V3 rewrite the commit log of the last patch (which is also summarized >> by Bjorn). >> https://lore.kernel.org/r/20210820100832.663931-1-chenhuacai@xxxxxxxxxxx >> >> V4 split the last patch to two steps. >> https://lore.kernel.org/r/20210827083129.2781420-1-chenhuacai@xxxxxxxxxxx >> >> V5 split Patch-9 again and sort the patches. >> https://lore.kernel.org/r/20210911093056.1555274-1-chenhuacai@xxxxxxxxxxx >> >> V6 split Patch-5 again and sort the patches again. >> https://lore.kernel.org/r/20210916082941.3421838-1-chenhuacai@xxxxxxxxxxx >> >> V7 stop moving vgaarb to drivers/pci because of ordering issues with >> misc_init(). >> https://lore.kernel.org/r/20211015061512.2941859-1-chenhuacai@xxxxxxxxxxx >> https://lore.kernel.org/r/CAAhV-H7FhAjM-Ha42Z1dLrE4PvC9frfyeU27KHWcyWKkMftEsA@xxxxxxxxxxxxxx >> >> >> Bjorn Helgaas (8): >> vgaarb: Factor out vga_select_framebuffer_device() >> vgaarb: Factor out default VGA device selection >> vgaarb: Move framebuffer detection to ADD_DEVICE path >> vgaarb: Move non-legacy VGA detection to ADD_DEVICE path >> vgaarb: Move disabled VGA device detection to ADD_DEVICE path >> vgaarb: Remove empty vga_arb_device_card_gone() >> vgaarb: Use unsigned format string to print lock counts >> vgaarb: Replace full MIT license text with SPDX identifier >> >> Huacai Chen (2): >> vgaarb: Move vga_arb_integrated_gpu() earlier in file >> vgaarb: Log bridge control messages when adding devices >> >> drivers/gpu/vga/vgaarb.c | 311 +++++++++++++++++++-------------------- >> 1 file changed, 154 insertions(+), 157 deletions(-) >> >> -- >> 2.25.1 >>
