[hardy] Battery brightness slider gone

[Chris Jones]

Binary package hint: gnome-power-manager

g-p-m used to have a slider in the battery section to control how much the backlight was dimmed when on battery power.
it was always a bit confusing that it was the opposite of the brightness slider in the AC tab, but now it seems to have gone entirely, which is even less helpful!

[Alex Willmer (alex-moreati)]

In 2.22.0-0ubuntu2 it would appear that both sliders are gone, I see only a slider to control screen blanking delay.

Is something like https://blueprints.launchpad.net/ubuntu/+spec/backlight-brightness-simplicity in the works? I.e. gpm managed back light brightness is determined during day to day adjustment. If so, I think it would still be good to have the sliders, for those who aren't aware of the keyboard shortcuts.

It may be too late for hardy. I would propose two sliders, one for mains mode and one for battery. Each slider controls back light brightness, from 0 to 100%. There is no reason I see that the back light must be dimmer on battery than on mains, it is just common practice. Having each slider have the same effect simplifies the mental workload and provides greater control.

Use case:
1. Alice charges her laptop in a dimly lit lab, whilst uploading field work. She has the back light set low to avoid glare.
2. Once charged she takes the laptop off mains and outside into bright daylight. She sets the back light to full brightness to gather data in the field, this level is stored by gpm as the default for battery mode.
3. Later the sun sets, she dims the back light, this level is stored as the default for battery mode.
4. Upon returning to the lab Alice places the laptop on charge, the original back light brightness is restored to the that stored for mains mode.

[Ludovico Cavedon (cavedon)]

I have the same problem, the brightness slide disappeared after Alpha 4.

[Chris Jones (cmsj)]

I spoke to Ted about this bug.
We have deliberately removed the AC brightness slider because it is a very confusing and unpredictable feature, and I have to say that I agree.
Until gnome is able to work sensibly with user adjusted brightness, it would be best not to annoy/confuse users. I regularly had to adjust my brightness because gnome was obeying settings and changing it.
I think this should be re-filed as a wishlist to have a sane startup value remembered and then the other brightness options to work relative to whatever the current brightness is.

[Walter_Wittel (wittelw)]

I would like to respectfully disagree with this being "invalid / file a wishlist" for the following reasons:
* The feature was available in 7.10 along with the confusing and unpredictable way it worked, but it was usable and better than nothing. As an end-user upgrading I would be very disappointed if I lost this functionality in an upgrade. As far as is possible I don't think upgrades should burn people or this will foster the kind of inertia widspread in the Windows world.
* I find the ability to adjust laptop brightness essential (see Alex's use case above, and add battery life).
* 6.1 Screen Dim Brightness in help has been revised to remove the (I expect planned but couldn't make it into Hardy) task bar slider, but the existing text is entirely inadequate. There should at least be pointers to how to find the laptop specific (in my case sudo /etc/acpi/sonybright.sh) scripts so that advanced users can control brightness from terminal.

To summarize this should be left as an open bug against Hardy and fixed ASAP. If a "correct" fix is too hard to provide in the next couple of months the old behavior should be reverted as an interim fix.

[Chris Jones (cmsj)]

for what it's worth, I think alex's use case is going to be confusing to users and personally I do not care if I am on AC or battery, I will adjust the brightness to the level I want and expect it to stay there.
users can still adjust the brightness with either keyboard shortcuts (e.g. on a laptop with brightness keys), or with the brightness panel applet, so your essential feature is taken care of, surely?
I would like to see g-p-m remember the level I set (ie behave like OS X brightness), but I do not think that it possible to change in hardy at this point of the cycle - there is no code to do it and release is in 2.5 weeks.
Either way it's not my decision to keep the current behaviour or revert to Gutsy brokenness, I'm just updating the bug status based on my understanding of the situation. Since I am not the package maintainer, my change is not authoritative.

[Alex Willmer (alex-moreati)]

I vote return to Gutsy behaviour. IMO both Gutsy and Hardy have broken behaviour, namely that g-p-m periodically overrides my set-by-Fn+Up/Down day to day choice on backlight brightness. At least with Gutsy I could choice the set point.

My ideal scenario would be to have the dialog with 0..100% sliders for the set point on battery & AC. However when I use the keyboard combination, that also configures the same set point for the current mode.

That's what I tried to describe above. Alex.

[Walter_Wittel (wittelw)]

Chris,

Thanks for the additional clarification. I do understand a change isn't likely before Hardy ships, I'd just like the issue addressed (but maybe it is simpler than I thought).

I am unable to find a "brightness panel applet" on my system and my brightness keys don't work (see BTW below). I probably just don't know where to look, but I can't find anything on my task bar, system menu, or in Synaptic searching for "brightness" or "applet" and browsing through the offerings. Note that I have upgraded from 7.10 rather than a clean install so maybe this is the problem.

A hint where to look for a brightness panel applet may very well address my (and other's) concerns.

I'm OK with setting one brightness and having it "stick" across both AC and battery, and a brightness panel applet would actually be better than going to the power management applet (I actually had a short cut for this I used it so often).

BTW, my brightness keys have never worked on my Vaio VGN-CR120E, but I did submit requested info at http://ubuntuforums.org/showthread.php?t=465491 so hopefully the keys will someday work. In the mean time a brightness panel applet would be my only relief from using Terminal to control my screen brightness. I hope I'm not in a Catch-22 where the keys have to work for the brightness panel to appear...

[Chris Jones (cmsj)]

Hi

Walter_Wittel wrote:
> I am unable to find a "brightness panel applet" on my system and my

If you right click on a panel and choose "Add to panel" it should be in
the applet selection box.

Cheers,
--
Chris Jones

[Walter_Wittel (wittelw)]

Chris, thanks for educating me on this! The brightness applet works great and completely addresses my concerns about adjusting the brightness.

Do you know if this will get turned on by default on a 7.10 upgrade? For laptops I think it should be put up on the panel by default right along with the volume control so it is more discoverable. Seems easier to remove if you don't want it (e.g. buttons work) than find it if you don't know where to look. Alternately maybe it will get covered in help (for those who RTFM :-)

Thanks for your help, and if you feel it is warranted I'd be happy to file a bug to get it turned on by default or added to help.

[Chris Jones (cmsj)]

I'm pretty sure the brightness applet is never on by default. I can certainly see the utility in having it - most laptops may have hardware keys for the brightness, but it seems possible that the control could also apply to desktops with LCDs, which will only have annoying menus on the monitor.
Either way, I suggest that making the brightness slider part of the default session should be filed as a different bug and maybe raised on the ubuntu-devel-discuss mailing list.

[Jason Eisner (jason-cs)]

I'm writing to support the original complaint and Alex's post at the top of this ticket.

Please! It's really important to be able to dim the screen automatically when switching to battery power, in order to save battery life. I relied on this in Gutsy. I go back and forth between AC and battery several times a day, and I obviously don't want to have to fiddle with the brightness keys or applet every time I hit the power cord.

(There may be several settings that can extend battery life -- screen brightness, CPU speed, hard disk spindown period, etc. I am surprised that gnome-power-manager doesn't allow all of these to be set differentially for AC and battery. Windows has allowed this for years, at least on Thinkpads.)

Chris, you write: "Personally I do not care if I am on AC or battery, I will adjust the brightness to the level I want and expect it to stay there." But I don't think users like you will be significantly inconvenienced by Alex's suggestion (whereas it would greatly help users like me). Here's why:

- Do you mean that you want to be permanently at 70%? And when you first set up the laptop on AC and set the brightness to 70%, it might change when you unplug it? That's not so horrible. You'll be slightly annoyed that you have to correct the brightness a second time now that you're on battery. But then you will live happily ever after, since you will have identical preferences set for AC and battery. Having to adjust the brightness twice seems a small price to pay for giving the rest of us the flexibility to have two different settings.

   (see https://blueprints.launchpad.net/ubuntu/+spec/backlight-brightness-simplicity)

- Or do you mean that you adjust your brightness to local lighting conditions every time you move the machine? In that case, I don't see why you would expect your adjustment to "stay there" when you plug or unplug the machine. Plugging or unplugging probably means you're moving to a new location, so why would you care if your previous adjustment sticks? You're about to readjust anyway.

Chris, you also write that Alex's use case is confusing. That's because Alex was outlining an interesting reversed situation where one might want a *brighter* screen on battery power. That is the reverse of the much more common situation where one wants to *dim* the screen on battery power to save battery. Think about this common situation.