Return of the 'Display Dimmed on Resume' gremlin.

[Frazer]

This problem seems to have popped up repeatedly across multiple releases and distros. Having spent quite a bit of time chasing down dead ends with no real insight or progress I would be interested to know if others out there have found a solution or work-around.

Symptoms are much as others have seen. After the laptop has woken from sleep, the display is fully dimmed. Brightness controls indicate full brightness but are non-functional. A restart is required to clear the problem.

Video driver is as shown below. Any ideas?

$ sudo lshw -c video
[sudo] password for phsphysics: 
*-display                 
    description: VGA compatible controller
    product: Core Processor Integrated Graphics Controller
    vendor: Intel Corporation
    physical id: 2
    bus info: pci@0000:00:02.0
    version: 02
    width: 64 bits
    clock: 33MHz
    capabilities: msi pm vga_controller bus_master cap_list rom
    configuration: driver=i915 latency=0
    resources: irq:26 memory:d0000000-d03fffff memory:c0000000-cfffffff ioport:3058(size=8) memory:c0000-dffff

[Frazer]

Found a solution to the problem that I perhaps should have anticipated.

I opened <system Settings>, <Hardware - Power Management> and opened the <AC Power> tab. The <Screen brightness> button was unchecked and the brightness slider greyed out, which I had assumed would mean that brightness changes were disabled. This is not the case. When the laptop suspends under AC power it changes to the brightness level set on this slider, whether the option is active or not. This overrides all other system settings. In order to ensure that the laptop returns to full brightness it is necessary to set the brightness level to full brightness.

My suspicion is that this operation is unintended so hopefully someone will see this and correct the bug in future releases.

[woodsmoke]

Hi
thank you very much for the information and the fix which you found.

Would you please go to "advanced reply" or whatever and change the title to yada yada LAPTOP

that might better provide information for others with your situation that are using laptops.

woodsmoke