Screen very dim after resume from suspend

bodhibrightnesssuspend

I'm unable to resume from 'Suspend to RAM'. It resumes properly, albeit with a very very dim screen (so dim I can barely make out the desktop). Trying to brighten the screen using the Fn keys doesn't work, and the only option is to switch the machine off and on.

I'm running Bodhi Linux 2.3 with onboard Intel graphics. I think the driver being used is i915, according to lsmod, but I could be wrong.

Output of uname -a and lsb-release -a:

Linux bodhiman 3.8.0-12-generic #21 SMP Tue Mar 12 17:39:30 CDT 2013 x86_64 86_64 x86_64 GNU/Linux

Distributor ID: Ubuntu
Description: Bodhi 2.3.0
Release: 12.04
Codename: precise

What can I do to diagnose this and fix it?

Best Answer

I think I solved the problem.

@drs proposed I install xbacklight to make it work but after installing it, I kept getting an error message saying "No outputs have backlight property"

A little bit of googling the error led me to 2 files in the /sys/class/backlight directory. The 2 files were

/sys/class/backlight/acpi_video0 /sys/class/backlight/intel_backlight

I tried,

echo 5 | /sys/class/backlight/acpi_video0/brightness and nothing changed

And then I tried,

echo 5 | /sys/class/backlight/intel_backlight/brightness and the screen went dark

So now I knew that I had to use the vendor driver (in this case intel) to change the brightness of the screen.

I opened /etc/default/grub and changed the line

GRUB_CMDLINE_LINUX_DEFAULT="splash quiet"

to

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

and then I ran the command

sudo grub-mkconfig -o /boot/grub/grub.cfg

and restarted the system.

Now my function keys to change the brightness are working and when I resume from 'suspend to RAM' it still resumes blank but now I can press the brightness keys just once to bring it back to pre-suspended brightness levels.

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