> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/redox-os/redox/llms.txt
> Use this file to discover all available pages before exploring further.

# Device Drivers

> Hardware drivers for Redox OS

## Overview

Redox OS uses a **userspace driver model** where device drivers run as separate processes outside the kernel. This microkernel approach provides better isolation, stability, and security compared to traditional monolithic kernels.

<Card title="Base Repository" icon="code" href="https://gitlab.redox-os.org/redox-os/base">
  View essential system components and drivers on GitLab
</Card>

## Key Features

<CardGroup cols={2}>
  <Card title="Userspace Drivers" icon="user">
    Drivers run as isolated userspace processes
  </Card>

  <Card title="Scheme-based" icon="network-wired">
    Accessed through Redox's URL-like scheme system
  </Card>

  <Card title="Hot-pluggable" icon="plug">
    Dynamic driver loading and unloading
  </Card>

  <Card title="Fault Isolation" icon="shield">
    Driver crashes don't bring down the system
  </Card>
</CardGroup>

## Driver Architecture

The Redox driver model follows the microkernel philosophy:

```text theme={null}
┌─────────────────────────────┐
│      Application            │
├─────────────────────────────┤
│   Device Scheme (driver)    │
├─────────────────────────────┤
│      Microkernel            │
├─────────────────────────────┤
│      Hardware               │
└─────────────────────────────┘
```

## Driver Initialization

Drivers are initialized through the init system:

```bash theme={null}
# Driver initialization script
requires_weak 00_base
pcid-spawner  # PCI device driver spawner
```

The PCI daemon (`pcid-spawner`) automatically loads drivers for detected hardware.

## Driver Categories

<Tabs>
  <Tab title="Storage">
    ### Storage Drivers

    Drivers for disk and storage devices:

    * **NVMe**: NVMe SSD support
    * **AHCI**: SATA controller support
    * **IDE**: Legacy IDE controller support
    * **USB Storage**: USB mass storage devices

    ```bash theme={null}
    # Storage devices appear as schemes
    ls /scheme/disk/
    ls /scheme/nvme0
    ```
  </Tab>

  <Tab title="Network">
    ### Network Drivers

    Network interface drivers:

    * **Intel**: Intel network adapters
    * **Realtek**: Realtek network cards
    * **Virtio**: Virtual network devices

    ```bash theme={null}
    # Network initialization
    notify smolnetd
    nowait dhcpd
    ```

    Network schemes available:

    ```toml theme={null}
    schemes = [
      "ip",    # IP networking
      "icmp",  # ICMP protocol
      "tcp",   # TCP protocol
      "udp",   # UDP protocol
    ]
    ```
  </Tab>

  <Tab title="Graphics">
    ### Display Drivers

    Graphics and display drivers:

    * **VESA**: VESA BIOS Extensions
    * **Intel HD**: Intel integrated graphics
    * **Virtio GPU**: Virtual GPU support

    ```toml theme={null}
    schemes = [
      "display.vesa",  # VESA display
      "display*",      # All displays
    ]
    ```
  </Tab>

  <Tab title="Input">
    ### Input Drivers

    Keyboard, mouse, and other input devices:

    * **PS/2**: PS/2 keyboard and mouse
    * **USB HID**: USB keyboards and mice
    * **Serial**: Serial port input

    ```toml theme={null}
    schemes = [
      "event",   # Event handling
      "serio",   # Serial I/O
      "pty",     # Pseudo-terminals
    ]
    ```
  </Tab>

  <Tab title="System">
    ### System Drivers

    Essential system device drivers:

    * **RTC**: Real-time clock
    * **Random**: Random number generation
    * **Null/Zero**: Null and zero devices

    ```bash theme={null}
    # System device files
    /dev/null -> /scheme/null
    /dev/random -> /scheme/rand
    /dev/zero -> /scheme/zero
    ```
  </Tab>
</Tabs>

## Base System Drivers

Essential drivers are included in the base package:

```toml theme={null}
[packages]
base = {}           # Essential system components and drivers
base-initfs = {}    # Initial ramdisk drivers
```

<Info>
  The `base` package includes core drivers needed for system boot and operation.
</Info>

## Driver Schemes

Drivers expose functionality through schemes:

### Base Schemes

```toml theme={null}
schemes = [
  "rand",    # Random number generator
  "null",    # Null device
  "zero",    # Zero device
  "log",     # System logging
]
```

### Network Schemes

```toml theme={null}
schemes = [
  "ip",      # IP protocol
  "icmp",    # ICMP protocol
  "tcp",     # TCP protocol
  "udp",     # UDP protocol
]
```

### IPC Schemes

```toml theme={null}
schemes = [
  "shm",         # Shared memory
  "chan",        # Channels
  "uds_stream",  # Unix domain sockets (stream)
  "uds_dgram",   # Unix domain sockets (datagram)
]
```

## PCI Driver Management

The PCI daemon manages PCI device drivers:

```bash theme={null}
# PCI device enumeration
pcid-spawner

# Automatically loads drivers for:
# - Network cards
# - Storage controllers
# - Graphics cards
# - USB controllers
```

## Network Configuration

Network drivers are configured through the init system:

```bash theme={null}
# Network initialization
notify smolnetd  # Network daemon
nowait dhcpd     # DHCP client
```

Network configuration files:

```toml theme={null}
# DNS server
[[files]]
path = "/etc/net/dns"
data = "9.9.9.9"

# IP address (QEMU default)
[[files]]
path = "/etc/net/ip"
data = "10.0.2.15"

# Router
[[files]]
path = "/etc/net/ip_router"
data = "10.0.2.2"

# Subnet mask
[[files]]
path = "/etc/net/ip_subnet"
data = "255.255.255.0"
```

## Audio Drivers

Audio device support:

```toml theme={null}
schemes = [
  "audio",  # Audio device access
]
```

## USB Support

USB drivers provide support for:

* USB storage devices
* USB input devices (keyboard, mouse)
* USB network adapters
* USB serial ports

## Driver Development

Developing drivers for Redox:

<Steps>
  <Step title="Implement the scheme interface">
    Create a scheme provider that implements the required operations
  </Step>

  <Step title="Register the scheme">
    Register your driver's scheme with the kernel
  </Step>

  <Step title="Handle requests">
    Process open, read, write, and other operations
  </Step>

  <Step title="Test in isolation">
    Test the driver in userspace before deployment
  </Step>
</Steps>

<Warning>
  Driver bugs only affect the driver process, not the entire system. This makes development and testing safer.
</Warning>

## Hardware Compatibility

For detailed hardware compatibility information, see:

<Card title="Hardware Support" icon="server" href="https://doc.redox-os.org/book/hardware-support.html">
  Complete list of supported hardware
</Card>

## Advantages of Userspace Drivers

<CardGroup cols={2}>
  <Card title="Stability" icon="check">
    Driver crashes don't crash the kernel
  </Card>

  <Card title="Security" icon="lock">
    Drivers run with limited privileges
  </Card>

  <Card title="Development" icon="code">
    Easier to develop and debug
  </Card>

  <Card title="Updates" icon="arrows-rotate">
    Drivers can be updated without rebooting
  </Card>
</CardGroup>

## Resources

<CardGroup cols={2}>
  <Card title="Base Repository" icon="gitlab" href="https://gitlab.redox-os.org/redox-os/base">
    Essential drivers and components
  </Card>

  <Card title="Hardware Support" icon="server" href="https://doc.redox-os.org/book/hardware-support.html">
    Supported hardware list
  </Card>

  <Card title="Redox Book" icon="book" href="https://doc.redox-os.org/book/">
    Driver development guide
  </Card>

  <Card title="Developer FAQ" icon="question" href="https://doc.redox-os.org/book/developer-faq.html">
    Common driver questions
  </Card>
</CardGroup>

## Maintainer

<Card title="Jeremy Soller (@jackpot51)" icon="user">
  Primary maintainer of base drivers
</Card>