Multiseat with systemd

Graphics / Linux Linux
1

Hey,

I already know that the nvidia driver creates the framebuffer after the X server is started, so I have to create an udev rule to make a “seat-master” (or is it “master-of-seat”)

on multiseat
Quote: …

Tag “master-of-seat”: if set this device is enough for a seat to be considered existent. This tag is
usually set for the framebuffer device of graphics cards. A seat hence consists of an arbitrary
number of devices marked with the “seat” tag, but (at least) one of these devices needs to be
tagged with “master-of-seat” before the seat is actually considered to be around.

…

Can someone give me an example to set this tag in an udev rule?

thanks,

jkfloris

2

The people of systemd where so kind to give me an example:
SUBSYSTEM==“graphics”, KERNEL==“fb[0-9]*”, TAG+=“seat”, TAG+=“master-of-seat”

Unfortunately, Nvidia doesn’t create a SUBSYSTEM==graphics or a KERNEL==fb0

$sudo udevadm info -a -p /sys/devices/pci0000:00/0000:00:03.0/0000:01:00.0/

looking at device ‘/devices/pci0000:00/0000:00:03.0/0000:01:00.0’:
KERNEL==“0000:01:00.0”
SUBSYSTEM==“pci”
DRIVER==“nvidia”
ATTR{vendor}==“0x10de”
ATTR{device}==“0x0615”
ATTR{subsystem_vendor}==“0x1043”
ATTR{subsystem_device}==“0x82fb”
ATTR{class}==“0x030000”
ATTR{irq}==“16”
ATTR{local_cpus}==“00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,0000000f”
ATTR{local_cpulist}==“0-3”
ATTR{numa_node}==“-1”
ATTR{dma_mask_bits}==“40”
ATTR{consistent_dma_mask_bits}==“32”
ATTR{enable}==“1”
ATTR{broken_parity_status}==“0”
ATTR{msi_bus}==“”
ATTR{boot_vga}==“1”

so I tried
SUBSYSTEM==“pci”, KERNEL==“0000:02:00.0”, TAG+=“seat”, TAG+=“master-of-seat”

but without success,

some more tips?

thanks

3

I used this:

DEVPATH==“/devices/pci0000:00/0000:00:0b.0/0000:06:00.0”, TAG+=“seat”, TAG+=“master-of-seat”

Which (I think) was able to be triggered to activate with:

sudo udevadm trigger --attr-match=vendor=‘0x10de’

4

I found this bug and some useful information thereabouts, but the conclusion was that it is not possible to get this working today with the standard packages:
878605 – systemd-logind: No way to setup multi-seat with two nvidia cards using proprietary drivers

5

Try this udev rule:

SUBSYSTEM=="drm", KERNEL=="card[0-9]*", ATTRS{vendor}=="0x10de", DRIVERS=="nvidia", TAG+="master-of-seat"

If your system does not have any /dev/dri/card* device files, try this other one:

SUBSYSTEM=="pci", ATTRS{vendor}=="0x10de", DRIVER=="nvidia", TAG+="seat", TAG+="master-of-seat"

And make sure you’re using Xorg server 1.16 or newer.