[PC-BSD Testing] E machines backlight problem

Ian McNulty ian-mcnulty at o2.co.uk
Sun Aug 26 14:40:55 PDT 2012


upgraded 9.0 to 9.1 RC1 and everything went smoothly except that the new  
kernel has inherited the same problem that the version 3 Linux kernel  
delivered to the E machine E525 ( and some acer laptops).

Basic problem is that the backlight is now switched off in PCBSD 9.1 which  
renders the laptop unusable unless this clumsy workaround is used:----

Now, that's a bit annoying to fix, and once Ubuntu is booted, you can't  
adjust your backlight. What we want to do is make ubuntu turn the  
backlight on automatically when you boot it and also, allow you to adjust  
your backlight once Ubuntu is booted. To do this:

  Open terminal.
  Type in:
Code:
gksudo gedit /etc/rc.local
and hit enter.

  Find:
Code:
exit 0
Above exit 0, put in:
Code:
setpci -s 00:02.0 F4.B=00
Save the file, and exit Gedit. If you get a popup message the "untitled  
document" isn't save, ignore it and close without saving.

  This fix will automatically make the backlight turn on upon boot.

  Now to ensure you can adjust your backlight once Ubuntu has booted:
  In terminal, enter the command:
Code:
gksudo gedit /etc/default/grub
In the file, find the line:
Code:
GRUB_CMDLINE_LINUX=""
Change that line to:
Code:
GRUB_CMDLINE_LINUX="acpi_osi=Linux"
Save the file. Exit gedit. If prompted to save untitled document, don't,  
choose close without saving.

  Now in terminal, type the command:
Code:
sudo update-grub
Wait for the process to finish then exit terminal. Reboot your PC.

  Once rebooted, you will notice the purple screen, but you don't need to  
adjust your backlight this time. You'll notice once you pass the boot  
purple screen, the backlight will go out. Don't worry. Wait a few seconds,  
then the backlight will come on, and ubuntu will boot up and you'll hear  
the Ubuntu startup sound.

  You will also notice that now you can also use the Fn key and use the  
right and arrow keys to adjust the brightness. (Or whatever keys you use  
to adjust the brightness). YAY! It's fixed.

Sorry if this should be addressed to the freebsd guys, but I hope the BSD  
community will sort this out a bit quicker than the Linux folk


More information about the Testing mailing list