Comment 36 for bug 999638

Machine: ASPIRE 5741
OS: Ubuntu 12.04 (kernel updated to 3.2.0-29-generic)
Symptom: screen remains black after resume from suspend, power LED is on, HDD light continuously blinking

Hi guys,

I had the above problem and have been looking for the solution.
Last night, I realise that it actually my machine displays login screen (and I can login) but LED back light is off so I couldn't see it.
This issue is very similar to what I had during the Ubuntu 12.04 installation, thus I tried a solution in the same line.

SOLUTION WORKED FOR MY CASE:
 1. open grub file by: sudo vim /etc/default/grub
 2. modify the corresponding lines as:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
GRUB_CMDLINE_LINUX="acpi_osi=Linux"

 3. reboot grub by: sudo update-grub.

I hope this helps some of you.