Date: Mon, 5 Apr 2021 13:30:10 GMT From: =?utf-8?B?RmVybmFuZG8gQXBlc3RlZ3XDrWE=?= <fernape@FreeBSD.org> To: doc-committers@FreeBSD.org, dev-commits-doc-all@FreeBSD.org Subject: git: b950b48ad7 - main - [handbook] Add reference to acpi_video(4) Message-ID: <202104051330.135DUA2m090635@gitrepo.freebsd.org>
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The branch main has been updated by fernape: URL: https://cgit.FreeBSD.org/doc/commit/?id=b950b48ad7ac9e148e81ecffa9100494806b29a5 commit b950b48ad7ac9e148e81ecffa9100494806b29a5 Author: Fernando Apesteguía <fernape@FreeBSD.org> AuthorDate: 2021-04-03 17:56:40 +0000 Commit: Fernando Apesteguía <fernape@FreeBSD.org> CommitDate: 2021-04-05 13:24:10 +0000 [handbook] Add reference to acpi_video(4) Section 12.13.1 explains how to configure ACPI. Add a small paragraph explaining how to use the acpi_video(4) driver so some laptop brightness keys can work. Approved by: gbe (mentor) Differential Revision: https://reviews.freebsd.org/D29567 --- .../content/en/books/handbook/config/_index.adoc | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/documentation/content/en/books/handbook/config/_index.adoc b/documentation/content/en/books/handbook/config/_index.adoc index 9eaca96dd2..364df797f9 100644 --- a/documentation/content/en/books/handbook/config/_index.adoc +++ b/documentation/content/en/books/handbook/config/_index.adoc @@ -1347,6 +1347,21 @@ ACPI and APM cannot coexist and should be used separately. The last one to load ACPI can be used to put the system into a sleep mode with `acpiconf`, the `-s` flag, and a number from `1` to `5`. Most users only need `1` (quick suspend to RAM) or `3` (suspend to RAM). Option `5` performs a soft-off which is the same as running `halt -p`. +The man:acpi_video[4] driver uses +link:https://uefi.org/specs/ACPI/6.4/Apx_B_Video_Extensions/Apx_B_Video_Extensions.html[ACPI +Video Extensions] to control display switching and backlight brightness. It must +be loaded after any of the DRM kernel modules. After loading the driver, +the kbd:[Fn] brightness keys will change the brightness of the screen. It is +possible to check the ACPI events by inspecting [.filename]#/var/run/devd.pipe#: + +[source,shell] +... +# cat /var/run/devd.pipe +!system=ACPI subsystem=Video type=brightness notify=62 +!system=ACPI subsystem=Video type=brightness notify=63 +!system=ACPI subsystem=Video type=brightness notify=64 +... + Other options are available using `sysctl`. Refer to man:acpi[4] and man:acpiconf[8] for more information. [[ACPI-comprob]]
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