I have an Acer Aspire 4736 Laptop running ubuntu 10.10. I recently used update manager to upgrade to 11.04.
After upgrading and rebooting, I had a problem with the following symptoms:
- Acer's BIOS Splash screen showed up followed by GRUB OS selection menu.
- After that the laptop's screen turned purple and then blank.
- A few seconds later I could hear the welcome sound but the laptop screen was blank.
- I connected an external monitor via HDMI and the image came up on the external monitor
And so I scoured the net and came across this forum thread and realise that my laptop's LCD panel was showing an image alright but the backlight was off - confirmed this by squinting closely at my laptop's LCD panel.
I followed unknown47's advice and restarted and it worked. If you have an Acer Aspire laptop and have a similar problem, do this:
- Bootup ubuntu.
- Connect external monitor.
- Edit /etc/rc.local and add before exit 0:
setpci -s 00:02.0 F4.B=00
- Edit /etc/default/grub and change
GRUB_CMDLINE_LINUX_DEFAULT = "quiet splash"to
GRUB_CMDLINE_LINUX_DEFAULT = "quiet splash acpi_osi = Linux"
- Execute the command sudo update-grub2
- And restart your computer.