DRIVER.CONF(5) Standards, Environments, and Macros DRIVER.CONF(5)


driver.conf - driver configuration files




Driver configuration files provide values for device properties. The
values override values provided by the devices themselves. Most modern
devices provide enough property values to make a driver configuration
file unnecessary.

The system associates a driver with its configuration file by name. For
example, a driver in /usr/kernel/drv called wombat has the driver
configuration file wombat.conf, also stored in /usr/kernel/drv,
associated with it. On systems that support 64-bit drivers, the driver
configuration file should be placed in the directory in which the 32-bit
driver is (or would be) located, even if only a 64-bit version is
provided. For example, a 64-bit driver stored in /usr/kernel/drv/sparcv9
stores its driver configuration file in /usr/kernel/drv.

The value of the name property is the node name. In a driver.conf file,
where the generic node name and compatible property associated with a
self-identifying devices are typically not used, the node name must be a
binding name. The binding name is the name chosen by the system to bind a
driver to the device. The binding name is either an alias associated with
the driver established by add_drv(8) or the driver name itself.

The syntax of a single entry in a driver configuration file takes one of
three forms:

name="node name" parent="parent name" [property-name=value ...];

In this form, the parent name can be either the binding name of the
parent nexus driver or a specific full pathname, beginning with a slash
(/) character, identifying a specific instance of a parent bus. If a
binding name is used then all parent nodes bound to that driver match. A
generic name (for example, pci) is not a valid binding name even though
it can appear in the full pathname of all intended parents.

Alternatively, the parent can be specified by the type of interface it
presents to its children.

name="node name" class="class name" [property-name=value ...];

For example, the driver for the SCSI host adapter can have different
names on different platforms, but the target drivers can use class scsi
to insulate themselves from these differences.

Entries of either form above correspond to a device information (devinfo)
node in the kernel device tree. Each node has a name which is usually the
name of the driver, and a parent name which is the name of the parent
devinfo node to which it will be connected. Any number of name-value
pairs can be specified to create properties on the prototype devinfo
node. These properties can be retrieved using the DDI property interfaces
(for example, ddi_prop_get_int(9F) and ddi_prop_lookup(9F)). The
prototype devinfo node specification must be terminated with a semicolon

The third form of an entry is simply a list of properties.

[property-name=value ...];

A property created in this way is treated as global to the driver. It can
be overridden by a property with the same name on a particular devinfo
node, either by creating one explicitly on the prototype node in the
driver.conf file or by the driver.

Items are separated by any number of newlines, SPACE or TAB characters.

The configuration file can contain several entries to specify different
device configurations and parent nodes. The system can call the driver
for each possible prototype devinfo node, and it is generally the
responsibility of the drivers probe(9E) routine to determine if the
hardware described by the prototype devinfo node is really present.

Property names must not violate the naming conventions for Open Boot PROM
properties or for IEEE 1275 names. In particular, property names should
contain only printable characters, and should not contain at-sign (@),
slash (/), backslash (\), colon (:), or square brackets ([]). Property
values can be decimal integers or strings delimited by double quotes (").
Hexadecimal integers can be constructed by prefixing the digits with 0x.

A comma separated list of integers can be used to construct properties
whose value is an integer array. The value of such properties can be
retrieved inside the driver using ddi_prop_lookup_int_array(9F).

Comments are specified by placing a # character at the beginning of the
comment string, the comment string extends for the rest of the line.


Example 1: Configuration File for a PCI Bus Frame Buffer

The following is an example of a configuration file called
ACME,simple.conf for a PCI bus frame buffer called ACME,simple.

# Copyright (c) 1993, by ACME Fictitious Devices, Inc.
#ident "@(#)ACME,simple.conf 1.3 1999/09/09"

name="ACME,simple" class="pci" unit-address="3,1"

This example creates a prototype devinfo node called ACME,simple under
all parent nodes of class pci. The node has device and function numbers
of 3 and 1, respectively; the property debug-mode is provided for all
instances of the driver.

Example 2: Configuration File for a Pseudo Device Driver

The following is an example of a configuration file called
ACME,example.conf for a pseudo device driver called ACME,example.

# Copyright (c) 1993, ACME Fictitious Devices, Inc.
#ident "@(#)ACME,example.conf 1.2 93/09/09"
name="ACME,example" parent="pseudo" instance=0

name="ACME,example" parent="pseudo" instance=1;


This creates two devinfo nodes called ACME,example which attaches below
the pseudo node in the kernel device tree. The instance property is only
interpreted by the pseudo node, see pseudo(5) for further details. A
property called debug-level is created on the first devinfo node which
has the value 1. The example driver is able to fetch the value of this
property using ddi_prop_get_int(9F).

Two global driver properties are created, whizzy-mode (which has the
string value "on") and debug-level (which has the value 3). If the driver
looks up the property whizzy-mode on either node, it retrieves the value
of the global whizzy-mode property ("on"). If the driver looks up the
debug-level property on the first node, it retrieves the value of the
debug-level property on that node (1). Looking up the same property on
the second node retrieves the value of the global debug-level property


pci(5), pseudo(5), sbus(5), scsi(5), add_drv(8), probe(9E),
ddi_getlongprop(9F), ddi_getprop(9F), ddi_getproplen(9F),
ddi_prop_get_int(9F), ddi_prop_lookup(9F), ddi_prop_op(9F)

Writing Device Drivers


To avoid namespace collisions between multiple driver vendors, it is
strongly recommended that the name property of the driver should begin
with a vendor-unique string. A reasonably compact and unique choice is
the vendor over-the-counter stock symbol.


The update_drv(8) command should be used to prompt the kernel to reread
driver.conf files.

September 16, 2018 DRIVER.CONF(5)