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Siciliano Subject: git: dbdfd83dcc - main - Acessibility Handbook: Add brightness List-Id: Commit messages for all branches of the doc repository List-Archive: https://lists.freebsd.org/archives/dev-commits-doc-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-doc-all@freebsd.org Sender: owner-dev-commits-doc-all@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: asiciliano X-Git-Repository: doc X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: dbdfd83dcce6ec37a75e80757ee7dfbc45dce3f4 Auto-Submitted: auto-generated Date: Mon, 24 Nov 2025 21:07:46 +0000 Message-Id: <6924c922.2dc90.2ae83b14@gitrepo.freebsd.org> The branch main has been updated by asiciliano: URL: https://cgit.FreeBSD.org/doc/commit/?id=dbdfd83dcce6ec37a75e80757ee7dfbc45dce3f4 commit dbdfd83dcce6ec37a75e80757ee7dfbc45dce3f4 Author: Alfonso S. Siciliano AuthorDate: 2025-11-24 21:05:29 +0000 Commit: Alfonso S. Siciliano CommitDate: 2025-11-24 21:05:29 +0000 Acessibility Handbook: Add brightness Add brightness section to the accessibility handbook. Reviewed by: pauamma_gundo.com Approved by: bcr Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D51285 --- .../en/books/accessibility/colors/_index.adoc | 118 +++++++++++++++++++++ 1 file changed, 118 insertions(+) diff --git a/documentation/content/en/books/accessibility/colors/_index.adoc b/documentation/content/en/books/accessibility/colors/_index.adoc index 6de26c0398..f3cda2106c 100644 --- a/documentation/content/en/books/accessibility/colors/_index.adoc +++ b/documentation/content/en/books/accessibility/colors/_index.adoc @@ -488,3 +488,121 @@ To use the yellow-blue.conf theme: # ln -s /usr/local/etc/portconfig/yellow-blue.conf /usr/local/etc/portconfig/theme.conf .... ==== + +[[brightness]] +== Brightness + +Screen brightness can be adjusted in various ways. +The available methods depend heavily on the hardware, so it's recommended to try the features described in the following sections. + +[[backlight]] +=== backlight + +The man:backlight[8] utility is included with the operating system. +It is used to set the brightness of devices located under [.filename]#/dev/backlight/#. + +The command `backlight -f _device_ _value_` sets the brightness of _device_ to _value_, where _value_ is an integer between 0 (dim) and 100 (bright). +If no device is specified, the default device [.filename]#/dev/backlight/backlight0# is considered. + +Example for setting the brightness of the default device to 50%: + +[source,shell] +.... +% backlight 50 +.... + +[NOTE] +==== +Unless the user belongs to the "video" group, the command needs to run as root. +==== + +[[acpi_video]] +=== acpi_video + +The man:acpi_video[4] driver, included with the operating system, uses the ACPI Video Extensions to control display switching and backlight brightness. +To load the kernel module, run: + +[source,shell] +.... +# kldload acpi_video +.... + +Brightness settings can be configured using extref:{handbook}config/#configtuning-sysctl[sysctl(8)]. +The following parameters are available: + +- hw.acpi.video._device_.levels: List of supported brightness levels. +- hw.acpi.video._device_.brightness: Current brightness level of the device. + +_device_ is a possible display device. +Example to set the brightness to 50% for the lcd0 device: + +[source,shell] +.... +% sysctl hw.acpi.video.lcd0.brightness <1> +hw.acpi.video.lcd0.brightness: 90 +% sysctl hw.acpi.video.lcd0.levels <2> +hw.acpi.video.lcd0.levels: 90 60 2 4 6 8 10 12 14 16 +18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 +54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 +90 92 94 96 98 100 +# sysctl hw.acpi.video.lcd0.brightness=50 <3> +hw.acpi.video.lcd0.brightness: 90 -> 50 +.... + +<.> `sysctl hw.acpi.video._device_.brightness` to view the current brightness level. +<.> `sysctl hw.acpi.video._device_.levels` to view the available levels. +<.> `sysctl hw.acpi.video._device_.brightness=50` to set the brightness to 50. + +[NOTE] +==== +man:acpi_video[4] should be loaded after any of the extref:{handbook}x11/#x-graphic-card-drivers[DRM] kernel modules. +==== + +[[xbrightness]] +=== xbrightness + +The package:x11/xbrightness[] utility can change the brightness via the extref:{handbook}x11[X Window System]. + +[source,shell] +.... +# pkg install xbrightness +.... + +The man:xbrightness[1] utility allows to set a value between 0 (darkness) and 65535 (full brightness). +Example for setting brightness to 50%: + +[source,shell] +.... +% xbrightness 32767 +.... + +[[xrandr]] +=== xrandr + +The package:x11/xrandr[] package is an extension of the X11 server that provides the man:xrandr[1] utility. +It allows you to configure various display properties, including brightness. +To install execute: + +[source,shell] +.... +# pkg install xrandr +.... + +The command `xrandr --output _monitor_ --brightness _brightness_` allows you to set the brightness for monitor to a value between 0 and 1.0. +To list the available monitors, run: + +[source,shell] +.... +% xrandr --listmonitors +Monitors: 2 + 0: +HDMI-1 1920/598x1080/337+0+0 HDMI-1 + 1: +eDP-1 1920/344x1080/194+1920+0 eDP-1 + +.... + +Example for setting brightness to 50% for HDMI-1: + +[source,shell] +.... +% xrandr --output HDMI-1 --brightness 0.5 +....