[xubuntu-users] Seeking help: computer wakes to dark screen

Joanna Hoyt joannahoyt at yahoo.com
Fri Jan 20 13:44:15 UTC 2017

I just installed 32-bit Xubuntu LTS 16.04 Xenial Xerus on a partition of my MacBook Pro 1,2 with a 2.16 GHz Intel Core Duo processor and 2GB 667 MHz DDR2 SDRAM. The brightness is fine at startup and during use, but after sleep the screen is very dark; I could barely see the screen asking me to enter my password, couldn't read anything else, had to use the power button to shut down. How can I set my computer so that it wakes up with reasonable screen brightness? I don't think it's a hardware issue; the computer wakes up brightly when running Mac OS X on the other partition. I've also seen online posts from Xubuntu users with different hardware reporting the same problem. 

Here are the fixes I've tried so far:
I thought it might be a brightness problem, since the F1 and F2 keys did not control screen brightness.I did the following:

Code: sudo leafpad /etc/default/grub
...to read: Code: GRUB_CMDLINE_LINUX="acpi_backlight=vendor" Saved file.
 Code: sudo update-grub

...After this the brightness control worked from the keyboard while the computer was staying awake after startup, but waking from sleep continued to be very dark and the keyboard commands did not increase brightness.

2.I tried changing settings in Power Manager under Settings, switching the 'sleep' and 'hibernate' actions from Lock Screen to Suspend; I saw no difference.

sudo apt-get update
sudo apt-get install xfce4-power-manager light-locker-settings
Light Locker appeared in my Settings, but when I click on the icon it didn't actually open a control panel--the icon just sat there. 

4:rm ~/.config/autostart/light-locker.desktopI did that and got a message saying 
rm: cannot remove '/home/lorraine/.config/autostart/light-locker.desktop': No such file or directory.
How do you decide whether to keep trying fixes, reinstall what you had before, or try another distro?

If keeping trying seems indicated: Some fixes start with going into 'system settings' and changing settings in a window I've not yet found. I can go into Settings, and thence into Power Manager, but that doesn't offer the exact options shown in the fixes. How should I access system settings, if they're separate from Settings?

Also, so far as I kow I don't have a swap partition configured. My Mac now has 3 partitions: 100 GB running Mac OS X (only using 20 GB at present), 50 GB running Xubuntu (very little of that used), 10 GB free space. I thought the swap partition was probably not important because I am not running near capacity on either of the established partitions, but I could be wrong; if so, how should I set up a swap partition on a Mac?
Any advice greatly appreciated. As you can see, I'm a raw newbie and realize I may be missing something obvious. Thanks for taking time to read this.
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