driver.conf - driver configuration files
driver.conf
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 capable of 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(1M) 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.
In addition to the vendor driver.conf files provided by the system and driver providers in /kernel and /platform, user-administered driver.conf files may be added in /etc/driver/drv. Files in /etc/driver/drv are available for local customizations to supplement the vendor driver configuration.
The format of an /etc/driver/drv driver.conf file is identical to that of a vendor driver.conf file.
For each driver, the vendor and admin driver.conf files are merged together and made available to the driver and system, as a merged set of device specifications with per-device properties and a global set of properties visible to every device instance bound to this driver.
These merged per-device and global properties are visible to an instance of the driver via the ddi_prop_lookup(9F) and related interfaces automatically, with no intervention by the driver required.
A driver that does provide configurable options by way of driver.conf should keep this property merge behavior in mind. Inverting the meaning of an option from one release to the next could cause problems for users that may have configured a system with the previous interpretation of that option.
A driver which has converted its configurable options from one revision to another may find it useful to convert older option configurations to the new supported set. The system maintains two separate property lists providing the default vendor properties and the admin customizations.
Each property originally derived from the vendor driver.conf file and then merged with an updated value will be entered both the vendor and admin property lists. Each list may be searched via ddi_prop_lookup(9F) as either the DDI_PROP_VENDOR or DDI_PROP_ADMIN, respectively. The property on the vendor list records the property's original value, while the property on the admin list provides the customization.
There is no property entry on the vendor list for a property derived solely from the admin driver.conf. Such properties have entries on the admin list only, providing the admin-specified value.
First, it is important to understand the format of a driver.conf entry. Each entry can be one of two types, specifying either a device information (devinfo) node as a parent specification or a set of properties globally available to all device instances bound to this driver.
An entry defining a device info node must specify the node's parent as either the binding name of the parent nexus driver, a pathname or by the class of interface presented to its children. Other properties on the parent specification define qualifiers required to correctly identify the specific device, and depend upon the parent driver or class of interface. An example of such a device qualifier property is 'target', used by SCSI hba adapters to identifier a specific device on its bus. Such qualifiers must be retained unchanged so that the system will continue to properly enumerate that device instance.
To modify one or more property values on such a parent specification, the targeted parent specification in the vendor driver.conf must be duplicated in the admin driver.conf, preserving each device qualifying property. Then the admin entry can be customized, supplementing it with additional or modified configurable options.
Parent specifications in the admin driver.conf that do not correspond to a match in the vendor driver.conf file are added to the list of device information nodes available to be potentially enumerated by the system for that driver.
The second type of driver.conf entry defines global properties for that driver. The admin driver.conf file can both update existing properties in the vendor driver.conf file with new values, and provide new global property name-value pairs available to all device instances bound to that driver.
The process of upgrading a Solaris system from one release to another involving delivering new versions of drivers including that driver's vendor driver.conf. It is desired that a system's earlier configuration should continue to work as before, with the new drivers and vendor driver.conf files together with the admin customized driver.conf files.
For a driver to work well under this model, each driver needs to be properly designed to present a disciplined set of configurable options. It would be best to carefully define a driver's options with this in mind and to fully describe the model presented in the driver's documentation or man page.
If a driver makes a change in its configuration options that would invalidate or supersede the admin settings, the driver should make the effort to discover the admin settings via the prior options and honor them.
For example, let's say a driver supports a timeout configuration in units of seconds. A new version of the driver now supports a finer timeout granularity in units of milliseconds. The new property should be named so it can be distinguished from the first. The driver can then look up the earlier property on the admin list and if found, continue to honor it.
/*
* Has the timeout been locally configured using the
* prior option of timeout in units of seconds?
*/
if (ddi_prop_lookup_int(DDI_DEV_T_ANY, dip,
DDI_PROP_ADMIN, "timeout",) ==
DDI_PROP_SUCCESS) {
if (n != 1) {
ddi_prop_free(ivalues);
return (EINVAL);
}
/* yes - convert our working timeout accordingly */
dip->ms_timeout = 1000 * ivalues[0];
/* record the new parameter setting for confirmation */
(void) ddi_prop_update_int(DDI_DEV_T_NONE,
dip, "ms-timeout", dip->ms_timeout);
ddi_prop_free(ivalues);
}
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"
debug-mode=12;
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 Using a Configuration File for a Pseudo Device DriverThe 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
debug-level=1;
name="ACME,example" parent="pseudo" instance=1;
whizzy-mode="on";
debug-level=3;
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(4) 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 (3).
Example 3 Modifying a Driver Global PropertyThe bge.conf provides default values for the receive and xmit rings.
# # The properties below represents the number of receive and send ring used. # For BCM5705, BCM5782, etc, there are only 1 receive ring and 1 send ring. # Otherwise, there can be up to 16 receive rings and 4 send rings. # bge-rx-rings = 16; bge-tx-rings = 1;
To customize the bge-tx-rings value, place a bge.conf file in /etc/driver/drv with the following line:
bge-tx-rings = 2;
When the bge driver is next loaded, the updated value can be observed with prtconf:
pci108e,534d (pci14e4,16a7), instance #0
System software properties:
name='bge-known-subsystems' type=int items=16
name='bge-rx-rings' type=int items=1
value=00000010
name='bge-tx-rings' type=int items=1
value=00000002
Additionally, prtconf -u can be used to display both the original default and the updated bge-tx-rings property values:
Admin global properties:
name='bge-tx-rings' type=int items=1
value=00000002
Vendor global properties:
name='bge-tx-rings' type=int items=1
value=00000001
Example 4 Modifying configurable values on a specific device
To modify the configurable parameter 'retries' on an sd device at target 0, lun 0 and 'queue-max' on the device target 1, lun 0, place an sd.conf file in /etc/driver/drv with the following lines:
name="sd" class="scsi" target=0 lun=0 retries=4; name="sd" class="scsi" target=1 lun=0 queue-max=16;
The updated values can be observed with prtconf:
sd, instance #1
System properties:
name='lun' type=int items=1
value=00000000
name='target' type=int items=1
value=00000000
name='class' type=string items=1
value='scsi'
name='retries' type=int items=1
value=00000004
name='ddi-devid-registrant' type=int items=1
value=00000001
sd, instance #2
System properties:
name='lun' type=int items=1
value=00000000
name='target' type=int items=1
value=00000001
name='class' type=string items=1
value='scsi'
name='queue-max' type=int items=1
value=00000010
name='ddi-devid-registrant' type=int items=1
value=00000001
With prtconf -u, the admin property values are displayed. The vendor property list in this case contains no properties as the vendor driver.conf contained no specification for such properties.
sd, instance #1
Admin properties:
name='retries' type=int items=1
value=00000004
sd, instance #2
Admin properties:
name='queue-max' type=int items=1
value=00000010
Example 5 Adding a New Device Instance
For purposes of illustration, suppose that the vendor sd.conf contains only the following parent specification:
name="sd" class="scsi" target=0 lun=0 max-retries=4;
and that it is desired to also support a target=1 device instance. Further suppose that target=0 should be configured with the max-retries parameter set to 10 and queueing set to 32, and that target=1 with max-retries to 10 and queueing to 64. Place the following lines in the sd.conf file in /etc/driver/drv:
name="sd" class="scsi" target=0 lun=0 max-retries=8 queue=32; name="sd" class="scsi" target=1 lun=0 max-retries=10 queue=64;
These changes can be observed with prtconf. For target 0, the vendor list contains the vendor setting for the number of retries and the updated value in the admin list. There was no specification for this target as delivered, so the vendor list for target 1 is empty and all specified parameters from the admin list are displayed.
sd, instance #1
System properties:
name='max-retries' type=int items=1
value=00000008
name='lun' type=int items=1
value=00000000
name='target' type=int items=1
value=00000000
name='class' type=string items=1
value='scsi'
name='queue' type=int items=1
value=00000020
name='ddi-devid-registrant' type=int items=1
value=00000001
Admin properties:
name='queue' type=int items=1
value=00000020
name='max-retries' type=int items=1
value=00000008
Vendor properties:
name='max-retries' type=int items=1
value=00000004
sd, instance #2 (driver not attached)
System properties:
name='queue' type=int items=1
value=00000040
name='max-retries' type=int items=1
value=0000000a
name='lun' type=int items=1
value=00000000
name='target' type=int items=1
value=00000001
name='class' type=string items=1
value='scsi'
name='ddi-devid-registrant' type=int items=1
value=00000001
Admin properties:
name='queue' type=int items=1
value=00000040
name='max-retries' type=int items=1
value=0000000a
name='lun' type=int items=1
value=00000000
name='target' type=int items=1
value=00000001
name='class' type=string items=1
value='scsi'
add_drv(1M), driver(4), pci(4), pseudo(4), scsi(4), 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 for Oracle Solaris 11.3
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(1M) command should be used to prompt the kernel to reread driver.conf files. Using modunload(1M) to update driver.conf continues to work in release 9 of the Solaris operating environment, but the behavior will change in a future release.
It is not currently possible to either remove or undefine a property, or to remove a parent specification, defined in a vendor driver.conf file with an addition to an /etc/driver/drv driver.conf file.