Passthrough (#1529)

* Add USB passthrough documentation

* Add front matter to HDMI passthrough

* Add front matter and Materialize some formatting in Switch docs

docs/pass.md

@@ -1,3 +1,8 @@
+---
+title: HDMI Video Passthrough
+description: "How to set up HDMI passthrough on PiKVM V4 Plus"
+---
+
 # HDMI Video Passthrough
 
 This is a new exclusive feature available only on **PiKVM V4 Plus**.

docs/switch.md

@@ -1,3 +1,8 @@
+---
+title: PiKVM Switch Multiport Extender Quickstart Guide
+description: "How to get started with PiKVM Switch Multiport Extender"
+---
+
 # PiKVM Switch Multiport Extender
 
 !!! info "Where to buy?"
@@ -6,9 +11,9 @@
     * [Canadian store](https://www.pishop.ca/product/pikvm-switch-multiport-extender/).
     * EU is coming!
 
-<img src="switch.png" width="400" />
+![PiKVM Switch](switch.png){ width="400" }
 
-* [PiKVM Switch Multiport Extender](switch_datasheet.pdf)
+[PiKVM Switch Datasheet (PDF)](switch_datasheet.pdf){ .md-button }
 
 The PiKVM Switch Multiport Extender enables one PiKVM device to view and control multiple target
 computers connected to each port. Target computers are viewed using HDMI video capture and then

docs/usb-passthrough.md

@@ -0,0 +1,60 @@
+---
+title: USB Passthrough
+description: "How to set up USB Passthrough on PiKVM"
+---
+
+# USB Passthrough
+
+For USB keyboards and mice connected to PiKVM directly, USB passthrough allows forwarding their input to the host system. This feature is available for all versions of PiKVM except the DIY version based on Pi Zero.
+
+Let's consider this setup:
+
+- [PiKVM V4 Plus](v4.md) connected to [PiKVM switch](switch.md);
+- A keyboard and a mouse connected to USB A ports on the PiKVM;
+- An external display connected to the PiKVM directly using HDMI out.
+
+![Example setup](usb-passthrough.png){ width="400" }
+
+With both HDMI passthrough and USB passthrough enabled, you would be able to do this:
+
+- Switch between Computer 1 and Computer 2 connected to PiKVM Switch;
+- Control them directly from this single keyboard/mouse pair (in addition to remote control);
+- See the video output from the selected host on the local display.
+
+## Enabling USB passthrough
+
+Follow these steps to enable USB passthrough on your PiKVM:
+
+1. [Log into your PiKVM](cheatsheet.md) as `root`, either via SSH, web console, or USB serial connection.
+
+2. You need KVMD 4.74+ to be able to use this feature. Update the PiKVM OS as `root`:
+
+    ```
+    [root@pikvm ~]# pikvm-update
+    ```
+
+3. PiKVM will reboot, log in as `root` again.
+
+4. Run the following command to change acces to read-write, enable USB passthrough, and change acces to read-only again:
+
+    ```
+    [root@pikvm ~]# rw; systemctl enable --now kvmd-localhid; ro
+    ```
+
+Once you've done that, you should be able to use your USB keyboard and mouse connected directly to your PiKVM to control the host.
+
+## Toggling USB passthrough
+
+Every once in a while you may want using keyboard/mouse to control your PiKVM instead of controlling a host. Once USB passthrough is enabled in the system, you can switch it on and off with shortcuts:
+
+- `LeftAlt, LeftAlt, K` (mnemonic **K**VM) disables keyboard/mouse grabbing and allows using the input devices with PiKVM locally, for example, for the console operating.
+
+- `LeftAlt, LeftAlt, H` (mnemonic **H**ost) switches back to the passthrough mode and passes keyboard-mouse events to the host.
+
+Press these keys **immediately** one after another: `LeftAlt`, then `LeftAlt` again, then the mnemonic key. 
+
+## Switching the PiKVM Switch channels
+
+If you have one or two PiKVM Switches, you can use `LeftAlt, LeftAlt, 1` (1-8) to switch between up to 8 channels.
+
+For three or more PiKVM Switches, you need to use double numbers, e.g., `LeftAlt, LeftAlt, 3, 2` (unit 3, channel 2).

mkdocs.yml

@@ -129,6 +129,7 @@ nav:
         - "Ethernet-over-USB": usb_ethernet.md
         - "Serial-over-USB": usb_serial.md
         - "GPIO (pins, relays, lamps, etc)": gpio.md
+        - "USB passthrough": usb-passthrough.md
     - "Advanced usage":
         - "Overriding system defaults": override.md
         - "On-boot configuration": on_boot_config.md