Messages in this thread | | | Date | Sat, 2 Jul 2022 22:06:45 -0700 | Subject | Re: [RFC] vgaarb: Add a module parm to use the first VGA device for boot | From | Randy Dunlap <> |
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Hi--
On 7/2/22 21:22, Cal Peake wrote: > Hi, > > I have a dual GPU system with the GPU in the first CPU PCIe slot for the > host and the GPU in the second CPU PCIe slot being passed through to a > virtual machine. > > Currently, the VGA arbiter enumerates through all VGA devices in the order > that they appear in on the bus with the last one ultimately getting the > assignment for boot device. > > This is a problem because once the VFIO PCI driver claims the second GPU, > all display output is lost -- just empty black screens on both cards. > > Setting VGA_ARB_MAX_GPUS to 1 helps a little: the X server will initialize > on the first GPU like it should, but there's no VTs to be found (i.e. > Alt-F1/F2/etc), just more black screens. > > Below is an attempt at a fix by creating a kernel param to have the VGA > arbiter use the first VGA device it finds for the boot device and then > subsequently ignore the rest for this task.
So that's vgaarb.use_first=1 right?
Seems worthy of some documentation in Documentation/admin-guide/kernel-parameters.txt, please.
-- ~Randy
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