safl.dk

PiKVM with v3 HAT

Bla bla bla

Installation

From the download-page, grab v3-hdmi-rpi4-latest.img.xz and write it to sdcard. Assemble the thing and let it boot.

Post-install

Login via the web-interface and dump yourself into the Shell/terminal and switch to root:

# Switch to root
su

Post-installation tasks in the PiKVM shell, as root do the following:

# Change storage to read/write mode
rw

# Change the hostname
hostnamectl set-hostname <the-new-hostname>

# Disable WiFi and Bluetooth
echo "dtoverlay=disable-wifi" >> /boot/config.txt
echo "dtoverlay=disable-bt" >> /boot/config.txt

# Disable janus, it relays information via google STUN servers for webrtc
systemctl disable --now kvmd-janus

# Enable the oled-display of the steel-case
systemctl enable --now kvmd-oled kvmd-oled-reboot kvmd-oled-shutdown
systemctl enable --now kvmd-information

# Change the password
passwd root

# Change password for ui
kvmd-htpasswd set admin

# Change storage to read-only mode
ro

H.264/WebRTC

It requires internet access and is by default configured to use a STUN server hosted by google. To avoid this, then disable the janus service and enable the static version:

systemctl disable --now kvmd-janus
systemctl enable --now kvmd-janus-static

See PiKVM-edid for more information about this.

Troubleshooting

A couple of notes on issues faced and how to solve them. For more, then

Garbled graphics

In case your BIOS/UEFI looks and behaves weird, here is an example of weird:

../../_images/video-garbled-02.png

then you probably needs the tweak the edid. For details look at PiKVM-edid. In my case using a MSI PRO Z690-A, then it looked like the picture above and the following custom-edit fixed it:

# Switch to root
su -

# Change storage-mode to read-write
rw

# Update the edid 1280x1024
echo "00FFFFFFFFFFFF005262888800888888
1C150103800000780AEE91A3544C9926
0F505425400001000100010001000100
010001010101D51B0050500019400820
B80080001000001EEC2C80A070381A40
3020350040442100001E000000FC0050
492D4B564D20566964656F0A000000FD
00323D0F2E0F0000000000000000014D
02030400DE0D20A03058122030203400
F0B400000018E01500A0400016303020
3400000000000018B41400A050D01120
3020350080D810000018AB22A0A05084
1A3030203600B00E1100001800000000
00000000000000000000000000000000
00000000000000000000000000000000
00000000000000000000000000000045" > /etc/kvmd/tc358743-edid.hex

# Update the edid 1920x1024
echo "00FFFFFFFFFFFF005262888800888888
1C150103800000780AEE91A3544C9926
0F505425400001000100010001000100
010001010101D32C80A070381A403020
350040442100001E7E1D00A050001940
3020370080001000001E000000FC0050
492D4B564D20566964656F0A000000FD
00323D0F2E0F000000000000000001C4
02030400DE0D20A03058122030203400
F0B400000018E01500A0400016303020
3400000000000018B41400A050D01120
3020350080D810000018AB22A0A05084
1A3030203600B00E1100001800000000
00000000000000000000000000000000
00000000000000000000000000000000
00000000000000000000000000000045" > /etc/kvmd/tc358743-edid.hex

# Refresh it
v4l2-ctl \
  --device=/dev/kvmd-video \
  --set-edid=file=/etc/kvmd/tc358743-edid.hex \
  --fix-edid-checksums

# Change storage-mode to read-only
ro

A power-cycle of the target-machine might be needed, it was for me. I am assuming that some video-subsystem probably needed re-negotiating. The above worked for me, however, you should probably have a look at the manual and how to “test” an edid, before you overwrite it like above. It is the same steps, but instead of writing the edid to tc358743-edid.hex then you write it to temporary file and run v4l2-ctl to see that it works.

Keyboard / mouse are not working

If you find that mouse / keyboard is not working then check:

  • Make sure you have the small USB-C bridge connected. That is the thing that lies with the ATX-pcb. Without it, then mouse/keyboard won’t work.

  • Make sure you are connected the USB-cabel from the PiKVM to the target-machine.

  • Make sure that USB works on your target-machine.

  • That you used the right image, e.g. if you use a v2 image with the v3 hat, then mouse/keyboard won’t work. This might seem obvious, but I made the mistake of just grabbing the first download-link on the download-page, instead of reading the page and grabbing the one for v3… so… if nothing else works, then this might be why.