Please read this before reporting a bug:
https://wiki.archlinux.org/title/Bug_reporting_guidelines
Do NOT report bugs when a package is just outdated, or it is in the AUR. Use the 'flag out of date' link on the package page, or the Mailing List.
REPEAT: Do NOT report bugs for outdated packages!
https://wiki.archlinux.org/title/Bug_reporting_guidelines
Do NOT report bugs when a package is just outdated, or it is in the AUR. Use the 'flag out of date' link on the package page, or the Mailing List.
REPEAT: Do NOT report bugs for outdated packages!
FS#26523 - [linux] LCD backlight cannot be set since 3.0.6
Attached to Project:
Arch Linux
Opened by Csaba Henk (csheemea) - Wednesday, 19 October 2011, 13:11 GMT
Last edited by Evangelos Foutras (foutrelis) - Thursday, 20 October 2011, 22:34 GMT
Opened by Csaba Henk (csheemea) - Wednesday, 19 October 2011, 13:11 GMT
Last edited by Evangelos Foutras (foutrelis) - Thursday, 20 October 2011, 22:34 GMT
|
DetailsDescription:
I cannot modify LCD backlight of my laptop by any means (neither by the keys which have these functions mapped to, nor by echoing to /sys/class/backlight/acpi_video0/brightness [cf. https://bbs.archlinux.org/viewtopic.php?id=113476]). It's just so bright all the time that it hurts my eyes. Additional info: * package version(s): linux 3.0.6-2 (used to work with 3.0.4; I have not booted to 3.0.6-1 so I can't tell for sure; however, the changes in beetwen 1 and 2 does not seem to contain anything related). # cat /sys/class/backlight/acpi_video0/device/uevent DRIVER=i915 PCI_CLASS=30000 PCI_ID=8086:0046 PCI_SUBSYS_ID=1025:040E PCI_SLOT_NAME=0000:00:02.0 MODALIAS=pci:v00008086d00000046sv00001025sd0000040Ebc03sc00i00 Steps to reproduce: Buy an Acer Aspire Timeline-X 1830T and install Arch onto it. |
This task depends upon
Closed by Evangelos Foutras (foutrelis)
Thursday, 20 October 2011, 22:34 GMT
Reason for closing: Fixed
Additional comments about closing: Reportedly fixed in linux 3.0.7-1.
Thursday, 20 October 2011, 22:34 GMT
Reason for closing: Fixed
Additional comments about closing: Reportedly fixed in linux 3.0.7-1.
I have the /sys/ file, but it is not user writable, so xbacklight might work through a different means. Hopefully one that is available for you.
xbacklight works by means of communicating with the X server, which is in turn capable of modifying the sysfs entries (and indeed, that is what it does, as a quick strace revealed). So it still seems to boil down to the sysfs thingies. (The ACPI interface of procfs was weeded out just recently, which is a possible alternative interface -- now gone. I thought of compiling a kernel with ACPI procfs re-added, but it sounds illogical to see behavioral differences in a kernel service due to a different configuration at the interface level.)
- the procfs changes I mention do not have relevance to this -- what have been taken out in Arch's config is the power subsystem related entries in /proc/acpi (CONFIG_ACPI_PROCFS_POWER); /proc/acpi/video is nonexistent both on 3.0.4 and 3.0.6 (the aforementioned Archlinux forum thread is what makes mention of /proc/acpi/video, that led me think it is relevant but as I say, there is no change in this respect).
- /sys/class/backlight/acpi_video0/brightness is half-broken on 3.0.4 too: I am able to echo any value into it but that does not have any effect (consequently, xbacklight is broken in 3.0.4 too). However, the special keys do work on 3.0.4, and the value of /sys/class/backlight/acpi_video0/brightness is updated accordingly when using them.