Auto dimming on brightness with spikes

[Victor Tuson Palau]

on the nexus7, I ran a 7 hours test that would run down the battery and logged every 15 minutes the contents of /sys/class/backlight/pwm-backlight/brightness

I started with it setup at 99 and unplugged the power supply, the second readin (15 min later) when down to 76. It continued as 76, but it seems that every hour it would jump back to 99 for a bit.

Hours running Screen brightness
0 99
0.25 76
0.5 76
0.75 76
1 99
1.25 76
1.5 76
1.75 76
2 99
2.25 76
2.5 76
2.75 76
3 99
3.25 76
3.5 76
3.75 76
4 99
4.25 76
4.5 76
4.75 76
5 99
5.25 76
5.5 76
5.75 76
6 99
6.25 76
6.5 76
6.75 76
7 99

[Chris Wayne (cwayne)]

Did you have 'dim screen to save power' on?

[Chris Wayne (cwayne)]

Depending on what your test actually did, it seems like maybe it is at 76 when the system is 'idle' (i.e. nothing is simulating clicks) and then jumping back up when a click is simulated. On my system, after about 1 minute of no clicks, the screen is dimmed. I think this is the normal behavior

[Chris Wayne (cwayne)]

I can now confirm this, running a similar test. Marking this bug confirmed, will charge up and do a full test tonight to re-confirm as well as get more data.

[Victor Tuson Palau (vtuson)]

yes auto-dim was on

[Matt Fischer (mfisch)]

Victor,

I am closing this bug as expected behavior. When no browser test is running there are no spikes, I stay consistently dimmed at 76. I can however, make it spike my simulating clicks/mouse input. For example, this output shows the brightness every 30 seconds:

76
76
76
76
76
76
76
76 <-- then I simulated a click with: xdotool click 1 and...
252 <-- The brightness spiked up to 252.
76 <-- then settled back to 76
76

I'm convinced that since your extension simulates browsing by scrolling and causing input events that it's pushing the brightness back to full. This is the expected and correct behavior for screen dimming.