Am 05.09.23 um 12:38 schrieb Jani Nikula:
On Tue, 05 Sep 2023, Sui Jingfeng <sui.jingf...@linux.dev> wrote:
From: Sui Jingfeng <suijingf...@loongson.cn>
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.
Well, you rarely find a board which can actually handle a single one :)
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.
The value 10 is incredibly arbitrary, and multiplied as a magic number
all over the place.
+1
$ 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)
In this example, all of the GPUs are driven by different drivers. What
good does a module parameter do if you have multiple GPUs of the same
model, all driven by the same driver module?
Completely agree. Question is what is the benefit for the end user to
actually specify this?
If you want the initial console on a different device than implement a
kernel options for vgaarb and *not* the drivers.
Regards,
Christian.
BR,
Jani.
$ 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(-)
