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Diffstat (limited to 'man/systemd-backlight@.service.xml')
| -rw-r--r-- | man/systemd-backlight@.service.xml | 27 |
1 files changed, 18 insertions, 9 deletions
diff --git a/man/systemd-backlight@.service.xml b/man/systemd-backlight@.service.xml index 431b27b..bb7f2b6 100644 --- a/man/systemd-backlight@.service.xml +++ b/man/systemd-backlight@.service.xml @@ -1,9 +1,9 @@ <?xml version="1.0"?> <!--*-nxml-*--> <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" - "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> + "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd"> <!-- SPDX-License-Identifier: LGPL-2.1-or-later --> -<refentry id="systemd-backlight@.service" conditional='ENABLE_BACKLIGHT' +<refentry id="systemd-backlight_.service" conditional='ENABLE_BACKLIGHT' xmlns:xi="http://www.w3.org/2001/XInclude"> <refentryinfo> @@ -31,13 +31,22 @@ <refsect1> <title>Description</title> - <para><filename>systemd-backlight@.service</filename> is a service that restores the display backlight - brightness at early boot and saves it at shutdown. On disk, the backlight brightness is stored in - <filename>/var/lib/systemd/backlight/</filename>. During loading, if the udev property - <option>ID_BACKLIGHT_CLAMP</option> is not set to false, the brightness is clamped to a value of at least - 1 or 5% of maximum brightness, whichever is greater. The percentage can be adjusted by specifying a - percentage (needs to be suffixed with <literal>%</literal>, e.g. <literal>30%</literal>) to the property - <option>ID_BACKLIGHT_CLAMP</option>.</para> + <para><filename>systemd-backlight@.service</filename> is a service that restores the brightness of + a display backlight or LED (e.g. keyboard backlight) device at early boot, and saves it at shutdown. + The brightness is stored in <filename>/var/lib/systemd/backlight/</filename>.</para> + + <para>On restoring brightness of a display backlight device, <command>systemd-backlight</command> reads + <varname>ID_BACKLIGHT_CLAMP</varname> udev property, that takes a boolean value or a percentage (needs to + be suffixed with <literal>%</literal>, e.g. <literal>30%</literal>). When a percentage is specified, the + saved brightness is clamped to a value of at least 1 or the specified percentage of the maximum + brightness, whichever is greater. When unset or set to true, the brightness is clamped in the same way + with percentage 5%. When false, the saved brightness will not be clamped, and loaded as is.</para> + + <para>On restoring brightness of a LED device, <command>systemd-backlight</command> reads + <varname>ID_LEDS_CLAMP</varname> udev property, that also takes a boolean value or a percentage. When a + percentage is specified, the saved brightness is clamped to the specified percentage of the maximum + brightness. When set to true, the brightness is clamped in the same way with percentage 5%. When unset or + set to false, the saved brightness will not be clamped, and loaded as is.</para> </refsect1> <refsect1> |