---
name: "siis"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/siis"
---

# siis(4)

SiliconImage Serial ATA Host Controller driver

## NAME

**siis** – SiliconImage Serial ATA Host Controller driver

## SYNOPSIS

To compile this driver into the kernel, place the following lines in your kernel configuration file:

**device pci** **device scbus** **device siis**

Alternatively, to load the driver as a module at boot time, place the following line in [loader.conf(5)](/loader.conf/5.md):

```
siis_load="YES"
```

The following tunables are settable from the [loader(8)](/loader/8.md):

- *hint.siis.**X**.msi*

  controls Message Signaled Interrupts (MSI) usage by the specified controller.

- *hint.siisch.**X**.pm\_level*

  controls SATA interface Power Management for the specified channel, allowing some power to be saved at the cost of additional command latency. Possible values:

  - 0

    interface Power Management is disabled (default);

  - 1

    device is allowed to initiate PM state change, host is passive.

    Note that interface Power Management is not compatible with device presence detection. A manual bus reset is needed on device hot-plug.

- *hint.siisch.**X**.sata\_rev*

  setting to nonzero value limits maximum SATA revision (speed). Values 1, 2 and 3 are respectively 1.5, 3 and 6Gbps.

## DESCRIPTION

This driver provides the [CAM(4)](/CAM/4.md) subsystem with native access to the SATA ports of controller. Each SATA port is represented to CAM as a separate bus with 16 targets. Most of the bus-management details are handled by the SATA-specific transport of CAM. Connected ATA disks are handled by the ATA protocol disk peripheral driver [ada(4)](/ada/4.md). ATAPI devices are handled by the SCSI protocol peripheral drivers [cd(4)](/cd/4.md), [da(4)](/da/4.md), [sa(4)](/sa/4.md), etc.

Driver features include support for Serial ATA and ATAPI devices, Port Multipliers (including FIS-based switching), hardware command queues (31 command per port), Native Command Queuing, SATA interface Power Management, device hot-plug and Message Signaled Interrupts.

The activity LEDs of the adapters supported by the **siis** driver can be controlled via the [led(4)](/led/4.md) API for localization or status reporting purposes.

## HARDWARE

The **siis** driver supports the following controller chips:

- SiI3124 (PCI-X 133MHz/64bit, 4 ports)

- SiI3131 (PCIe 1.0 x1, 1 port)

- SiI3132 (PCIe 1.0 x1, 2 ports)

- SiI3531 (PCIe 1.0 x1, 1 port)

## FILES

- */dev/led/siisch\**

  identification LED device nodes

## SEE ALSO

[ada(4)](/ada/4.md), [ata(4)](/ata/4.md), [cam(4)](/cam/4.md), [cd(4)](/cd/4.md), [da(4)](/da/4.md), [led(4)](/led/4.md), [sa(4)](/sa/4.md)

## HISTORY

The **siis** driver first appeared in FreeBSD 8.0.

## AUTHORS

Alexander Motin ⟨*mav@FreeBSD.org*⟩