Red Hat Bugzilla – Bug 473600
[Regression] Screen brightness problems on Acer laptop
Last modified: 2010-03-21 15:36:27 EDT
Description of problem: I just installed F10 on my Acer TravelMate 3260 laptop. The ACPI stuff like bluetooth, screen brightness etc. is handled by acer-wmi module. In Fedora 9, brightness control worked perfectly. In Fedora 10, I am having the problems with both control of brightness in preferences, and the on-screen display which appears when I change brightness using the Fn+Arrow keys. The problem is described in detail below. Version-Release number of selected component (if applicable): gnome-power-manager-2.24.1-3.fc10.i386 How reproducible: Always Steps to Reproduce: 1. In g-p-m Preferences, "On AC Power", Set display brightness to XX% doesn't work 2. Control brightness using Fn+Left/Right arrow keys, OSD shoots beyond max and min limits Actual results: 1. The brightness does not reduce/increase 2. The OSD fill increases even after full brightness, and decreases even after zero Expected results: 1. Change should take place instantly 2. OSD fill limits should be between actual limits of brightness only Additional info: I can control brightness software-"manually" from the console, by manually writing and reading entries from /sys/devices/platform/acer-wmi/backlight/acer-wmi. Here is sample output: [rohan@fedora acer-wmi]$ pwd /sys/devices/platform/acer-wmi/backlight/acer-wmi [rohan@fedora acer-wmi]$ cat max_brightness 15 [rohan@fedora acer-wmi]$ cat actual_brightness 10 [rohan@fedora acer-wmi]$ echo 5 | sudo tee brightness 5 [rohan@fedora acer-wmi]$ cat brightness 5 [rohan@fedora acer-wmi]$ cat actual_brightness 5 [rohan@fedora acer-wmi]$
This output might be helpful: [rohan@fedora ~]$ lshal | grep laptop_panel info.capabilities = {'laptop_panel'} (string list) info.category = 'laptop_panel' (string) laptop_panel.access_method = 'general' (string) laptop_panel.num_levels = 16 (0x10) (int)
I could reproduce this exact same bug on Ubuntu 8.10 livecd which uses GNOME 2.24 too. Hence I concluded that this might be an upstream bug, and filed one here - http://bugzilla.gnome.org/show_bug.cgi?id=563165
This is something I noticed of Fedora 10 - whenever I change the brightness using the keyboard (Fn-Left/Right Arrow) key, I get this message in dmesg: [rohan@fedora Shared]$ dmesg ACPI: EC: non-query interrupt received, switching to interrupt mode ACPI: EC: non-query interrupt received, switching to interrupt mode ACPI: EC: non-query interrupt received, switching to interrupt mode This happens regardless whether acer_wmi module is loaded or unloaded. Could this be indicative of some problem, or is it harmless?
Same thing on Fedora 10, Acer Travelmate 6492. The symptom is as described by Rohan.
Update: I tried reproducing this situation on recently released Debian lenny, and there the indicator and slider works perfectly. Debian has g-p-m 2.22.1.
The exact same problem exists in Fedora 11 Alpha and Ubuntu 9.04 Alpha 5, so I am prompted to think it is a gnome 2.24 and 2.26 problem.
Does this still happen with the version in fedora rawhide, or the version of the Fedora 11 beta live cd?
Hi Richard, I am on the live system of Fedora 11 snap1. I can confirm that this bug is definitely solved, the increments in the OSD are proper, and g-p-m settings change apply instantly. Is the fix local to fedora, or would it work on other distributions like Ubuntu? Thanks a lot.
Ok, closing this then.
I have purchased an Acer Aspire AS-3810T 354G32N and installed Centos (presently 5.4). I already have an Acer TravelMate C112TCI with the same Centos installation. In none of the two computers do the Fn-direction keyboard keys RIGHT and LEFT work. Those are the ones that set screen brightness. On the 3810T that is a serious problem due to the extremely bright screen that Linux is showing. I am writing from the 3810T and these are my kernel brightness documented scripts and uname outputs: --------------------------------------------------------------------------- [root@aspire scripts]# chmod 755 *brightness [root@aspire scripts]# ./*get-bright* org.freedesktop.Hal.Device.UnknownError Missing or empty environment variable(s). This script should be started by hald. [root@aspire scripts]# cd linux [root@aspire linux]# ls hal-luks-remove-linux hal-system-power-hibernate-linux hal-luks-setup-linux hal-system-power-reboot-linux hal-luks-teardown-linux hal-system-power-set-power-save-linux hal-system-lcd-get-brightness-linux hal-system-power-shutdown-linux hal-system-lcd-set-brightness-linux hal-system-power-suspend-linux [root@aspire linux]# ./*get-bright* org.freedesktop.Hal.Device.LaptopPanel.NotSupported No ACPI method found [root@aspire linux]# [root@aspire linux]# uname -a Linux aspire.workgroup 2.6.18-164.6.1.el5.centos.plusPAE #1 SMP Wed Nov 4 10:17:55 EST 2009 i686 i686 i386 GNU/Linux [root@aspire linux]# ---------------------------------------------------------------------------- Thanks for your help
I found a solution that works for the Aspire 3810T and, I hope, for others, the merit of an anonymous expert. Please find it at CentOS Issue ID 004246, URL http://bugs.centos.org/view.php?id=4246 It writes a brightness level directly to a register of the pci VGA device. I see this bug was closed. Was another solution already posted, or was it an error? One continues to find more complaints over several Linux distros and Acer computer models. Best regards to all fernando mansito