Bug 16960

Summary: Two devices control LCD backlight on Asus laptop
Product: hal Reporter: John <bogustrumper02>
Component: haldAssignee: David Zeuthen (not reading bugmail) <zeuthen>
Status: RESOLVED NOTOURBUG QA Contact:
Severity: normal    
Priority: medium CC: danny.kukawka
Version: unspecified   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments: Full lshal output

Description John 2008-08-02 08:48:02 UTC
Created attachment 18081 [details]
Full lshal output

Two udis exist to control the backlight.  Interacting with either of them can change the backlight, but changing the level of one also changes the range of the other.  This results in the brightness often resetting itself to zero while reporting (via kpowersave, for example) that it is at 100% brightness.

My system is an Asus Z35f, with an intel i915 graphics card and a Core2 Duo processor.  I have encountered this problem on two separate distributions running this (0.5xx) version of HAL.

output of hald --version: 
HAL package version: 0.5.11rc2

output of lshal | grep backlight:
udi = '/org/freedesktop/Hal/devices/computer_backlight_0'
  info.udi = '/org/freedesktop/Hal/devices/computer_backlight_0'  (string)
  linux.subsystem = 'backlight'  (string)
  linux.sysfs_path = '/sys/devices/virtual/backlight/asus-laptop'  (string)
udi = '/org/freedesktop/Hal/devices/computer_backlight'
  info.udi = '/org/freedesktop/Hal/devices/computer_backlight'  (string)
  linux.subsystem = 'backlight'  (string)
  linux.sysfs_path = '/sys/devices/virtual/backlight/acpi_video0'  (string)

Full lshal attached.
Comment 1 Danny Kukawka 2008-08-26 02:28:18 UTC
HAL simply provides interfaces to sysfs. And since the kernel provides two brightness interfaces in the sysfs it's a kernel and not a HAL issue. Please report it to you distro or the kernel ML. 

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