Multi-seat Confiuration

ACS supports limited multi-seat config to allow individual set of input subsystem devices for each of the connect GPU. This support is mostly desired in Automotive/Infotainment subsystems where the screens can be used as different panels or different usages.

Setup

HW Requirements (validated only on AMDGPU setup)

1. APU + DGPU setup.
2. Card0 and Card1 should be enumerated under /dev/dri/ folder.
3. Each APU and dGPU should be connected with individual monitor, mouse and keyboard.
4. Connect extra pair of keyboard and mouse which could be easily distinguished (different vendor or product id) with already connected pair.

One Time Setup

Step 1:

To make multi-seat setup, make sure to comment the "additional-devices=card1" config in weston.ini.

Step 2: Create udev rule to create a new seat

• Create a new udev rules file under /etc/udev/rules.d/ by following the below naming convention.

<priority>-<device name>.rules

• In the above naming convention, priority number determines the order of rule execution. Lesser the number, the higher the priority. So, use the priority number less than existing rules under /etc/udev/rules.d/

  Ex: New rule 69-graphics-seat.rules in the below figure is created with priority 69.

  Copy the below contents into 69-graphics-multseat.rules and update the parameters from next step.

SUBSYSTEM=="drm", KERNEL=="card1", KERNELS=="0000:c7:00.0", TAG+="master-of-seat", 
ENV{ID_SEAT}="seat1"
SUBSYSTEM=="drm", KERNEL=="renderD129", KERNELS=="0000:c7:00.0", ENV{ID_SEAT}="seat1"
SUBSYSTEM=="graphics", KERNEL=="fb1", KERNELS=="0000:c7:00.0", ENV{ID_SEAT}="seat1"
SUBSYSTEM=="input", ATTRS{devnum}=="9", ATTRS{idVendor}=="1bcf", ATTRS{idProduct}=="08a0", 
OWNER="acs2", ENV{ID_SEAT}="seat1"
SUBSYSTEM=="input", ATTRS{devnum}=="4", ATTRS{idVendor}=="1a2c", ATTRS{idProduct}=="4c5e", 
OWNER="acs2", ENV{ID_SEAT}="seat1"

• First 3 lines in above udev script will assign card1 to seat1.
• Last 2 lines will assign specific keyboard and mouse to seat1.
• By default, system will always have CARD0 assigned to DGPU, and CARD1 to APU.
• In above example, update keys like KERNELS, idVendor etc. with the system specific parameters and OWNER with system user-name.
• To get the details of KERNELS of card1, idVendor, idProduct of Keyboard and Mouse connected to the system, run the devices.sh script present under "/share/weston/devices.sh"

$ sudo chmod 777 <path>/share/weston/devices.sh
$ cd <path>/share/weston && ./devices.sh

Sample output of devices.sh script

--------------Card1 details-------------------

/dev/dri/card1 value of KERNELS: 0000:c7:00.0
fb1 value of KERNELS: 0000:c7:00.0
render not value of KERNELS: 0000:c7:00.0

---------------Mouses connected-----------------
Mouse 1:
Vendor ID: 1bcf
Product ID: 08a0
Device No: 009

Mouse 2:
Vendor ID: 1bcf
Product ID: 08a0
Device No: 008

---------------Keyboards connected-----------------
Keyboard 1:
Vendor ID: 1a2c
Product ID: 4c5e
Device No: 004

Keyboard 2:
Vendor ID: 1a2c
Product ID: 4c5e
Device No: 002

• Update the KERNELS param in rule file for card1, fb1 and renderD129 entries based on output from device.sh script.
• Select the keyboard and mouse based on information from device.sh and update the idVendor and idProduct, devnum params in rule file.
• ATTR{devnum} value can change on reboot so, we need to check this value used in rule on each reboot.
• When there is a change update the rule and run below command to reload new rule.

Reload udev rules:
$ sudo udevadm control --reload-rules

Trigger udev to apply the new rules:
$ sudo udevadm trigger

Step 3 : Copy service files

1. Execute the below commands to copy the multi-seat related service files present under /opt/amdgpu/share/weston to respective locations.

$ sudo cp <path>/share/weston/mysession.service /etc/systemd/system
$ sudo cp <path>/share/weston/mysession.target /etc/systemd/user
$ sudo cp <path>/share/weston/weston.service /etc/systemd/user
$ sudo cp <path>/share/weston/weston.socket /etc/systemd/user

2. Edit /etc/systemd/system/mysession.service file as shown below and update User and Group with system's username.

3. Edit /etc/systemd/user/weston.service file and update the config file path if needed.

4. Run the below commands to reload systemd

$ systemctl daemon-reload
$ systemctl --user daemon-reload

Step 4 : Disable GDM

1. Execute the below commands to disable GDM which internally disables GUI

$ sudo systemctl disable gdm3
$ sudo reboot

2. After system is rebooted, TTY terminal will appear for login. Login with credentials.

With this, One Time Setup for Multi-Seat is completed. These steps are not required unless Multi-Seat setup is disabled.

Launching ACS on Multi-Seat

1. Run the below command to list the seats connected to the system. In the case of multi-seat, it should list seat0 and seat1. If not, onetime setup is not done properly, please check the steps again for One Time Setup.

$ loginctl list-seats

2. Run script device.sh and verify the device number returned from script is same as used in udev rule, if not udpate the rule and reload the rule

Reload udev rules:
$ sudo udevadm control --reload-rules

Trigger udev to apply the new rules:
$ sudo udevadm trigger

3. Edit /share/weston/multi-seat-setup.sh file to update the user-name and seat name as per the system.
4. Optional : update the config file path in multi-seat-setup.sh with custom config file path.
5. Execute /share/weston/multi-seat-setup.sh script file from target machine TTY terminal. [Note: This script shall not be executed from remote machine terminal.]
6. Result - ACS desktop should appear on both the monitors each controllable with set of keyboard and mouse.

Disable Multi-Seat setup

1. Move or delete the rule file created in /etc/udev/rules.d/
2. Enable GDM - systemctl set-default graphical.target
3. sudo reboot