brightness slider doesn't hit max/min value sometimes even when all the way left/right

This may be related to this issue:

#1077054 in some cases, sliding the brightness slider to the right (brighter) actually dims the screen more

If the slider "maxes" at 232 when it should max at 255, when you touch the slider and move it lower (left) you may move from 255 through 232 as it moves, thus giving the appearance of the value going up before it starts going down.

When I used a mouse and move it as fast as possible from near minimum to the max, this is what I get:

ubuntu@nexus7-265143b8:~$ /usr/lib/gnome-settings-daemon/gsd-backlight-helper --get-brightness
45

I can reproduce this using the arrow keys to move the slider. In fact it's even reproducible on my HP laptop. Seems to be related to how fast the slider is moved.

Possibly related to:
https://bugs.launchpad.net/gnome-control-center/+bug/893851

jmleddy is going to get that patch into Q and then we'll retry these. Meanwhile I will assign to myself.

Porting the fix from https://bugs.launchpad.net/gnome-control-center/+bug/893851 forward did NOT solve this bug.

Started playing with this one again today, and I found that the behavior has become even stranger... if I slide the slider up, the screen brightness increases, but... the moment I release the slighter, brightness clamps back down to 0.

After sliding it all the way to the right, I get this:

$ /usr/lib/gnome-settings-daemon/gsd-backlight-helper --get-brightness
0

If I flail the mouse wildly while hitting enter on that command, I do get a value:

$ /usr/lib/gnome-settings-daemon/gsd-backlight-helper --get-brightness
178

And, if I try this:

$ sudo /usr/lib/gnome-settings-daemon/gsd-backlight-helper --set-brightness 255

The screen gets bright for 0.5s, and then gets dark again.

Here's an interesting experiment: I put the --get-brightness command into a loop, executing every 0.1 seconds, and then tried to move the slider around more or less gently, over the course of ~30s. Zero values accurately indicate that the screen has become quite dim (this is just to give you an idea of how flickery it is)

http://paste.ubuntu.com/1618012/

you need to shut down luxd ... which is the interim solution we use for shortcutting the ambient light sensor to the brightness level ...

this function is currently being ported to gnome-settings-daemon and should not interfere with the manual settings by then ... for now, disable luxd if you want to adjust brightness by hand.

oh, and please note that the luxd script was added much later than this bug was filed, they are two distinct issues (reproducing this bug will only be possible without luxd running)

a new ubuntu-defaults-nexus7 was uploaded with luxd removed. please check if the issue still persists with a recent nexus7 image

This bug was fixed in the package ubuntu-defaults-nexus7 - 0.54

---------------
ubuntu-defaults-nexus7 (0.54) raring; urgency=low

  * drop luxd (LP: #974260 ), (LP: #1077096) (LP: #1126836)
 -- Oliver Grawert <email address hidden> Thu, 14 Mar 2013 10:12:10 +0100