Unless otherwise specified in an attribute description all attributes are optional
and will accept UTF-8 input.
- type: A file that can be read to obtain the type of attribute. This attribute is
- mandatory.
+ type:
+ A file that can be read to obtain the type of attribute.
+ This attribute is mandatory.
The following are known types:
+
- enumeration: a set of pre-defined valid values
- integer: a range of numerical values
- string
All attribute types support the following values:
- current_value: A file that can be read to obtain the current
+ current_value:
+ A file that can be read to obtain the current
value of the <attr>.
This file can also be written to in order to update the value of a
This attribute is mandatory.
- default_value: A file that can be read to obtain the default
+ default_value:
+ A file that can be read to obtain the default
value of the <attr>
- display_name: A file that can be read to obtain a user friendly
+ display_name:
+ A file that can be read to obtain a user friendly
description of the at <attr>
- display_name_language_code: A file that can be read to obtain
+ display_name_language_code:
+ A file that can be read to obtain
the IETF language tag corresponding to the
"display_name" of the <attr>
"enumeration"-type specific properties:
- possible_values: A file that can be read to obtain the possible
+ possible_values:
+ A file that can be read to obtain the possible
values of the <attr>. Values are separated using
semi-colon (``;``).
"integer"-type specific properties:
- min_value: A file that can be read to obtain the lower
+ min_value:
+ A file that can be read to obtain the lower
bound value of the <attr>
- max_value: A file that can be read to obtain the upper
+ max_value:
+ A file that can be read to obtain the upper
bound value of the <attr>
- scalar_increment: A file that can be read to obtain the scalar value used for
+ scalar_increment:
+ A file that can be read to obtain the scalar value used for
increments of current_value this attribute accepts.
"string"-type specific properties:
- max_length: A file that can be read to obtain the maximum
+ max_length:
+ A file that can be read to obtain the maximum
length value of the <attr>
- min_length: A file that can be read to obtain the minimum
+ min_length:
+ A file that can be read to obtain the minimum
length value of the <attr>
Dell specific class extensions
- --------------------------
+ ------------------------------
On Dell systems the following additional attributes are available:
- dell_modifier: A file that can be read to obtain attribute-level
+ dell_modifier:
+ A file that can be read to obtain attribute-level
dependency rule. It says an attribute X will become read-only or
suppressed, if/if-not attribute Y is configured.
- modifier rules can be in following format:
- [ReadOnlyIf:<attribute>=<value>]
- [ReadOnlyIfNot:<attribute>=<value>]
- [SuppressIf:<attribute>=<value>]
- [SuppressIfNot:<attribute>=<value>]
+ modifier rules can be in following format::
+
+ [ReadOnlyIf:<attribute>=<value>]
+ [ReadOnlyIfNot:<attribute>=<value>]
+ [SuppressIf:<attribute>=<value>]
+ [SuppressIfNot:<attribute>=<value>]
- For example:
- AutoOnFri/dell_modifier has value,
- [SuppressIfNot:AutoOn=SelectDays]
+ For example::
+
+ AutoOnFri/dell_modifier has value,
+ [SuppressIfNot:AutoOn=SelectDays]
This means AutoOnFri will be suppressed in BIOS setup if AutoOn
attribute is not "SelectDays" and its value will not be effective
Enumeration attributes also support the following:
- dell_value_modifier: A file that can be read to obtain value-level dependency.
+ dell_value_modifier:
+ A file that can be read to obtain value-level dependency.
This file is similar to dell_modifier but here, an
attribute's current value will be forcefully changed based
dependent attributes value.
- dell_value_modifier rules can be in following format:
- <value>[ForceIf:<attribute>=<value>]
- <value>[ForceIfNot:<attribute>=<value>]
+ dell_value_modifier rules can be in following format::
+
+ <value>[ForceIf:<attribute>=<value>]
+ <value>[ForceIfNot:<attribute>=<value>]
+
+ For example:
+
+ LegacyOrom/dell_value_modifier has value:
+ Disabled[ForceIf:SecureBoot=Enabled]
- For example,
- LegacyOrom/dell_value_modifier has value:
- Disabled[ForceIf:SecureBoot=Enabled]
This means LegacyOrom's current value will be forced to
"Disabled" in BIOS setup if SecureBoot is Enabled and its
value will not be effective through sysfs until this rule is
Contact: Divya Bharathi <Divya.Bharathi@Dell.com>,
Mario Limonciello <mario.limonciello@dell.com>,
Prasanth KSR <prasanth.ksr@dell.com>
-
+Description:
Devices support various authentication mechanisms which can be exposed
as a separate configuration object.
For example a "BIOS Admin" password and "System" Password can be set,
reset or cleared using these attributes.
+
- An "Admin" password is used for preventing modification to the BIOS
settings.
- A "System" password is required to boot a machine.
Change in any of these two authentication methods will also generate an
uevent KOBJ_CHANGE.
- is_enabled: A file that can be read to obtain a 0/1 flag to see if
+ is_enabled:
+ A file that can be read to obtain a 0/1 flag to see if
<attr> authentication is enabled.
This attribute is mandatory.
- role: The type of authentication used.
+ role:
+ The type of authentication used.
This attribute is mandatory.
- Known types:
- bios-admin: Representing BIOS administrator password
- power-on: Representing a password required to use
- the system
- mechanism: The means of authentication. This attribute is mandatory.
+ Known types:
+ bios-admin:
+ Representing BIOS administrator password
+ power-on:
+ Representing a password required to use
+ the system
+
+ mechanism:
+ The means of authentication. This attribute is mandatory.
Only supported type currently is "password".
- max_password_length: A file that can be read to obtain the
+ max_password_length:
+ A file that can be read to obtain the
maximum length of the Password
- min_password_length: A file that can be read to obtain the
+ min_password_length:
+ A file that can be read to obtain the
minimum length of the Password
- current_password: A write only value used for privileged access such as
+ current_password:
+ A write only value used for privileged access such as
setting attributes when a system or admin password is set
or resetting to a new password
This attribute is mandatory when mechanism == "password".
- new_password: A write only value that when used in tandem with
+ new_password:
+ A write only value that when used in tandem with
current_password will reset a system or admin password.
Note, password management is session specific. If Admin password is set,
same password must be written into current_password file (required for
password-validation) and must be cleared once the session is over.
- For example:
+ For example::
+
echo "password" > current_password
echo "disabled" > TouchScreen/current_value
echo "" > current_password
pending BIOS attribute changes. Also, an uevent_KOBJ_CHANGE is
generated when it changes to 1.
- 0: All BIOS attributes setting are current
- 1: A reboot is necessary to get pending BIOS attribute changes
- applied
+ == =========================================
+ 0 All BIOS attributes setting are current
+ 1 A reboot is necessary to get pending BIOS
+ attribute changes applied
+ == =========================================
Note, userspace applications need to follow below steps for efficient
BIOS management,
+
1. Check if admin password is set. If yes, follow session method for
password management as briefed under authentication section above.
2. Before setting any attribute, check if it has any modifiers
Reading from it returns a list of supported options encoded as:
- 'builtinsafe' (Built in safe configuration profile)
- 'lastknowngood' (Last known good saved configuration profile)
- 'factory' (Default factory settings configuration profile)
- 'custom' (Custom saved configuration profile)
+ - 'builtinsafe' (Built in safe configuration profile)
+ - 'lastknowngood' (Last known good saved configuration profile)
+ - 'factory' (Default factory settings configuration profile)
+ - 'custom' (Custom saved configuration profile)
The currently selected option is printed in square brackets as
- shown below:
+ shown below::
- # echo "factory" > /sys/class/firmware-attributes/*/device/attributes/reset_bios
- # cat /sys/class/firmware-attributes/*/device/attributes/reset_bios
- # builtinsafe lastknowngood [factory] custom
+ # echo "factory" > /sys/class/firmware-attributes/*/device/attributes/reset_bios
+ # cat /sys/class/firmware-attributes/*/device/attributes/reset_bios
+ # builtinsafe lastknowngood [factory] custom
Note that any changes to this attribute requires a reboot
for changes to take effect.
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