Ubuntu
linux package

  1. Bug #934707
  2. Comment #15

Comment 15 for bug 934707

Revision history for this message
Terry Jones (terryjones28056) wrote : Re: emachine e725 boots to valid display with no backlight

Seth sorry for the long time to reply, I had given up on this bug and do not check my email often.

"Can you specify exactly the last release or kernel version you used that worked properly? Thanks!Can you specify exactly the last release or kernel version you used that worked properly? Thanks!"
 I cannot say exactly but it was around June 2011. I did not report a bug because I was hoping some updated would fix it.

"1. What's the output of 'cat /sys/class/backlight/acpi_video0/device/firmware_node/path'? Does it change based on whether or not you pass acpi_osi=Linux?"
terry@terry-eMachines-E725:~$ cat /sys/class/backlight/acpi_video0/device/firmware_node/path
\_SB_.PCI0.OVGA (I am now using acpi_osi= with a space after the =)

"2. Does the acpi_video0 backlight work when you pass acpi_osi=Linux?"
Yes, but I have to use the brightness adjustment otherwise it is a black screen.
The brightness keys are reversed ( Fn+Dim makes brighter)

3. Did the function keys work to adjust the brightness in older Ubuntu versions?
Can't say for sure as I never needed to adjust.

I'm suspecting that several things are broken about the backlight implementation in the bios on this machine that are worked around using a special driver in Windows.
That is a good posibility.