From: Sui Jingfeng <suijingfeng@xxxxxxxxxxx> On a machine with multiple GPUs, a Linux user has no control over which one is primary at boot time. This series tries to solve above mentioned problem by introduced the ->be_primary() function stub. The specific device drivers can provide an implementation to hook up with this stub by calling the vga_client_register() function. Once the driver bound the device successfully, VGAARB will call back to the device driver. To query if the device drivers want to be primary or not. Device drivers can just pass NULL if have no such needs. Please note that: 1) The ARM64, Loongarch, Mips servers have a lot PCIe slot, and I would like to mount at least three video cards. 2) Typically, those non-86 machines don't have a good UEFI firmware support, which doesn't support select primary GPU as firmware stage. Even on x86, there are old UEFI firmwares which already made undesired decision for you. 3) This series is attempt to solve the remain problems at the driver level, while another series[1] of me is target to solve the majority of the problems at device level. Tested (limited) on x86 with four video card mounted, Intel UHD Graphics 630 is the default boot VGA, successfully override by ast2400 with ast.modeset=10 append at the kernel cmd line. $ lspci | grep VGA 00:02.0 VGA compatible controller: Intel Corporation CoffeeLake-S GT2 [UHD Graphics 630] 01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Caicos XTX [Radeon HD 8490 / R5 235X OEM] 04:00.0 VGA compatible controller: ASPEED Technology, Inc. ASPEED Graphics Family (rev 30) 05:00.0 VGA compatible controller: NVIDIA Corporation GK208B [GeForce GT 720] (rev a1) $ sudo dmesg | grep vgaarb pci 0000:00:02.0: vgaarb: setting as boot VGA device pci 0000:00:02.0: vgaarb: VGA device added: decodes=io+mem,owns=io+mem,locks=none pci 0000:01:00.0: vgaarb: VGA device added: decodes=io+mem,owns=none,locks=none pci 0000:04:00.0: vgaarb: VGA device added: decodes=io+mem,owns=none,locks=none pci 0000:05:00.0: vgaarb: VGA device added: decodes=io+mem,owns=none,locks=none vgaarb: loaded ast 0000:04:00.0: vgaarb: Override as primary by driver i915 0000:00:02.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=none:owns=io+mem radeon 0000:01:00.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=none:owns=none ast 0000:04:00.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=none:owns=none v2: * Add a simple implemment for drm/i915 and drm/ast * Pick up all tags (Mario) v3: * Fix a mistake for drm/i915 implement * Fix patch can not be applied problem because of merge conflect. v4: * Focus on solve the real problem. v1,v2 at https://patchwork.freedesktop.org/series/120059/ v3 at https://patchwork.freedesktop.org/series/120562/ [1] https://patchwork.freedesktop.org/series/122845/ Sui Jingfeng (9): PCI/VGA: Allowing the user to select the primary video adapter at boot time drm/nouveau: Implement .be_primary() callback drm/radeon: Implement .be_primary() callback drm/amdgpu: Implement .be_primary() callback drm/i915: Implement .be_primary() callback drm/loongson: Implement .be_primary() callback drm/ast: Register as a VGA client by calling vga_client_register() drm/hibmc: Register as a VGA client by calling vga_client_register() drm/gma500: Register as a VGA client by calling vga_client_register() drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 11 +++- drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 13 ++++- drivers/gpu/drm/ast/ast_drv.c | 31 ++++++++++ drivers/gpu/drm/gma500/psb_drv.c | 57 ++++++++++++++++++- .../gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 15 +++++ drivers/gpu/drm/i915/display/intel_vga.c | 15 ++++- drivers/gpu/drm/loongson/loongson_module.c | 2 +- drivers/gpu/drm/loongson/loongson_module.h | 1 + drivers/gpu/drm/loongson/lsdc_drv.c | 10 +++- drivers/gpu/drm/nouveau/nouveau_vga.c | 11 +++- drivers/gpu/drm/radeon/radeon_device.c | 10 +++- drivers/pci/vgaarb.c | 43 ++++++++++++-- drivers/vfio/pci/vfio_pci_core.c | 2 +- include/linux/vgaarb.h | 8 ++- 14 files changed, 210 insertions(+), 19 deletions(-) -- 2.34.1
