3.4 KiB
Dynamic USB configuration
PiKVM emulates a number of USB devices to ensure normal operation: keyboards, mouse and mass storage drive. Also an additional relative mouse may be present (like on PiKVM V4 by default), or a user configured USB Ethernet or Serial port.
In rare cases, the host BIOS/UEFI may not understand such a large number of emulated devices on single USB port, so some of them may need to be disabled. USB reconfiguration usually requires a reboot, but it is possible to temporarily disable already configured existing emulated devices.
!!! warning This feature is experimental. Due to the imperfections of the kernel modules, rarely a dynamic configuration change can lead to a kernel panic and reboot.
For PiKVM V3 and V4 this is considered more secure because they have two independent watchdog systems
that can bring devices back to life after a timeout of a few minutes.
Command-line utility
The kvmd-otgconf utility allows you to view and modify the USB configuration on the fly.
It requires root permission and can be used for example from a web terminal.
View the config:
# kvmd-otgconf
+ hid.usb0 # Keyboard
+ hid.usb1 # Absolute Mouse
+ hid.usb2 # Relative Mouse
+ mass_storage.usb0 # Mass Storage Drive
Each line represents a device (function). First comes plus or minus sign (the device on or off), then the name of the device and its description.
Disabling the device:
[root@pikvm ~]# kvmd-otgconf --disable-function mass_storage.usb0
+ hid.usb0 # Keyboard
+ hid.usb1 # Absolute Mouse
+ hid.usb2 # Relative Mouse
- mass_storage.usb0 # Mass Storage Drive
Enabling the device:
[root@pikvm ~]# kvmd-otgconf --enable-function mass_storage.usb0
+ hid.usb0 # Keyboard
+ hid.usb1 # Absolute Mouse
+ hid.usb2 # Relative Mouse
+ mass_storage.usb0 # Mass Storage Drive
Web UI menu
Using the pseudo-GPIO driver, you can also control devices via the menu in the web interface. Read about GPIO basics here.
To setup the menu, use kvmd-otgconf --make-gpio-config to generate the configuration, and combine it
with your existing one in /etc/kvmd/override.yaml in a usual way.
# kvmd-otgconf --make-gpio-config
kvmd:
gpio:
drivers:
otgconf:
type: otgconf
scheme:
hid.usb0:
driver: otgconf
mode: output
pin: hid.usb0
pulse:
delay: 0
hid.usb1:
driver: otgconf
mode: output
pin: hid.usb1
pulse:
delay: 0
hid.usb2:
driver: otgconf
mode: output
pin: hid.usb2
pulse:
delay: 0
mass_storage.usb0:
driver: otgconf
mode: output
pin: mass_storage.usb0
pulse:
delay: 0
view:
table:
- - '#Keyboard'
- '#hid.usb0'
- hid.usb0
- - '#Absolute Mouse'
- '#hid.usb1'
- hid.usb1
- - '#Relative Mouse'
- '#hid.usb2'
- hid.usb2
- - '#Mass Storage Drive'
- '#mass_storage.usb0'
- mass_storage.usb0