Configuring KDE with Multiple GPUs - FreeBSD 13.1 on Talos II
reddit / freebsd

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TheThirdLegion · 2023-03-30 20:27

Hello all, I'm working on getting FreeBSD 13.1 ppc64le installed and
setup on my Talos II workstation and I'm trying to parse out how to
configure X11 to use the discrete GPU in the system. The system has
both VGA output from the motherboard (via an AST2500 BMC) and an AMD
WX7100. I'd like to switch over to the dGPU, however I'm not sure how
to go about doing so. My understanding from working with this system
under Linux is that the bootloader will need to unload the kernel
modules for the AST2500 and fallback to the dGPU, and I'm not sure how
to accomplish something similar under FreeBSD.

Currently, KDE will load up properly under the AST2500, but xrandr
does not recognize the second GPU.

So far I've attempted setting the GPU in
/usr/local/etc/X11/xorg.conf.d/10-drivers.conf and specifying the GPU
and PCIe bus which lead to it not loading on the AST2500, however the
GPU dobees not load either. Similarly, I've tried blindly configuring
the screens as well, and deliberately leaving out the monitor attached
to the AST2500 which nets the same behavior.

Included below is my rc.conf and any help would be appreciated!

`clear_tmp_enable="YES"`
`sendmail_enable="NONE"`
`hostname="talos"`
`ifconfig_ix1="DHCP"`
`sshd_enable="YES"`
`ntpdate_enable="YES"`
`ntpd_enable="YES"`
`# Set dumpdev to "AUTO" to enable crash dumps, "NO" to disable`
`dumpdev="AUTO"`
`dbus_enable="YES"`
`sddm_enable="YES"`
`kld_list="amdgpu"`

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can-of-bees · 2023-03-31 13:00

I used to have an Nvidia Optimus laptop - I want to say that kernel
modules were loaded for both GPUs, but then Xorg was configured to
only use the Intel chip. It's been a while though, so maybe I'm
remembering the setup incorrectly.

I'll look for old Xorg configs - I know I have some - and see if
there's anything worthwhile that might help. Otherwise, have you
looked at Optimus setup tutorials? There are some in the forums, IIRC.

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Xerxero · 2023-03-31 13:03

Get the pci slot nr and configure xorg to use that one instead of the
onboard one.

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TheThirdLegion · 2023-03-31 23:20

That was one direction I went down, however the Optimus tutorials I
saw mainly relied on some Nvidia-specific packages to automatically do
the xorg configs.

The Raptor Computing wiki also mentioned using the "OutputClass"
option within the config to set a primary GPU, which seemed to not be
an acceptable option in the config.

The forums certainly had a bunch of interesting options, though most
relied on something Nvidia-specific. Might be worth trying to toss a
(otherwise non-functional) Nvidia GPU in there and see what configs
those utilities spit out and try that.

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grahamperrin · 2023-04-01 17:56

> AST2500 BMC

I'm not familiar with this hardware. Is it driven by `amdgpu`?

> WX7100

 finds nothing.

In output from `pciconf -lv`, what are the relevant sections?