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Bug#671116: linux-image-3.2.0-2-686-pae: LCD backlight setting doesn't work on HP ProBook 451x

Package: linux-2.6
Followup-For: Bug #671116

Good news. After applying the latest BIOS update from HP, setting the
LCD backlight started to work through the sysfs interface. I had to
remove the acpi_backlight kernel boot parameter and then it started to
work. "echo 10 > /sys/class/backlight/acpi_video0/brightness" changes
the LCD brightness.

But the keyboard shortcuts still don't work. acpi_listen gives me the
following when pressing Fn+F7 (brightnesdown) and Fn+F8 (brightnessup):

# acpi_listen 
video/brightnessup BRTUP 00000086 00000000 K
video/brightnessdown BRTDN 00000087 00000000 K

It looks like some events need to be added in acpi-support, which should
transfer this bug to acpi-support. But there is another way perhaps?...

For anyone having this problem, here is how to do the BIOS update:
- the URL from where to download the BIOS updates is the following:
- first download and install "ROM Image for HP Notebook System BIOS
  (68GPI) Remote ROM Flash - SSM Compliant" (for F.10)
- then download and install "HP Notebook System BIOS Update" (for F.20)
- I had a Windows XP on a separate partition, so it was easy; if you
  don't have a Windows installation, I think you'll need to use the
  FreeDOS bootable media that HP has available

-- System Information:
Debian Release: wheezy/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: i386 (i686)

Kernel: Linux 3.2.0-2-686-pae (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

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