[kde-linux] Re: KDE 4.6.3 update messed up my TwinView setup?

[Duncan]

Mark Knecht posted on Mon, 13 Jun 2011 05:47:05 -0700 as excerpted:

> On Sun, Jun 12, 2011 at 9:05 PM, Duncan <1i5t5.duncan at cox.net> wrote:
>> Mark Knecht posted on Sun, 12 Jun 2011 06:47:37 -0700 as excerpted:
>>
>>> I've been using NVidia's TwinView where my two 1920x1080 monitors are
>>> treated like one large 3940x1080 screen. This worked fine in 4.6.2 but
>>> with the Gentoo update yesterday to 4.6.3 it's now treating the two
>>> monitors like separate 1920x1080 screens.
>>>
>>> I'm looking but haven't found it yet. Is there a setting somewhere
>>> that allows me to set it back the way it was? The
>>> SystemSettings->Display&Monitor tab shows it's supposed to be a single
>>> 3940x1080 monitor, so it appears to be more of a desktop issue than
>>> purely a display issue.
>>
>> Try... kcontrol[,] hardware, display and monitor, multiple monitors.
>> FWIW I believe you'll need USE=xinerama to get that kcontrol module.
>>
> For clarity, you're suggesting I add USE-xinerama to how I build my
> machine? I'm happy to try it but it seems a rather radical step for a
> minor KDE upgrade.
> 
> OK, before I change USE flags Size & Orientation shows a single
> monitor3840X1080 which is correct.
> 
> Multiple Monitors has all 5 check boxes checked and shows :
> 
> Display 1:0,0,1920,1080 Display2:1920,0,1920,1080
> 
> The Identify all Displays gives me a '1' on the left monitor and a '2'
> on the right monitor. My mouse stops at the left side of monitor 1 and
> the right side of monitor 2. However I have two separate desktops with
> different wallpaper and (frustratingly) all new windows seem to open on
> the right monitor, not the left monitor even though it says to open
> unmanaged windows on Monitor 1.
> 
> Please clarify about the xinerama flag (I've never used it) and I'll
> give it a try.

In terms of the xinerama USE flag, equery hasuse xinerama tells me that 
kwin, plasma-workspace, and systemsettings (ksplash too, but I don't 
believe it's implicated here), are the kde-base packages that have the 
flag.  Oh, and qt-gui is of course a kde dependency and has the flag 
too.  There's some other non-kde-related packages too, but they're not 
apropos, here.  So it's not like changing it and running emerge --newuse 
will trigger a rebuild of all of kde.

And AFAIK, the packages where it is most critical default-use it, plus I 
believe it's set in some of the profiles.  So if you don't have it set 
specifically, it'll still be on for at least those packages, and 
depending on your profile, may be on in general.

But, if you have the multiple monitors kcm (kcontrol module), I believe 
that means it was on for the packages in question as I believe it's that 
flag that controls whether that module is built and installed.  So if you 
have the module (as you do), you shouldn't have to worry about the flag, 
it was on for what needed it already.

The nVidia proprietary drivers are as I believe are aware, a black-box I 
by policy won't have anything to do with, so to the degree that they're 
different and potentially making the situation more complex, as they may 
well be doing, you'll have to either work that end out yourself or find 
someone else to help with it.  However, if the layout is working as it 
should with a normal native randr enabled X/KMS driver...

There are two separate pieces of kde that are affected by multi-monitor 
setups, plasma and kwin.  Both of these are still under quite active new-
feature development and as a result are often buggy, particularly with 
multiple monitors as support for various multi-monitor features is only 
now coming online, and it's still not what one would exactly describe as 
stable, for sure.  If one takes the view that solid single-monitor 
support is a prerequisite to good multi-monitor functionality, then this 
is only natural, especially if one also takes the view, as I definitely 
do, that 4.5 was the first truly normal-people usable version, what 
SHOULD have been 4.0, and supposes that a .0 would bring single-monitor 
support to full stability, 4.6 is then comparable to a 4.1 beta (where 
multi-monitor stability might be considered a 4.1 feature), with previews 
and sometimes working versions of the new functionality there, but not 
really ready for prime-time.

Anyway...

The multiple-monitor kcm under discussion is the kwin multi-monitor 
configuration.  You mention having all five checkboxes checked.  But if 
you read the options, they enable multi-monitor support for various 
things, when your preference as posted is to have them treated as if they 
were a single BIG monitor.  Thus, it's likely that you really want some 
of these options UNCHECKED.  That's why I was pointing you at this kcm, 
since it controls much of kwin's behavior in this regard, but didn't 
specify a particular option, as once you're there, I figured you could 
decide for yourself which options you wanted checked and unchecked.

Of course, this kcm has been available for some time, since 4.4 or 
earlier I believe.  However, as I explained, multi-monitor support is 
still under development and the way kwin supports some of these options 
may have changed, thus changing the observed behavior with an upgrade 
even if you didn't change any of the options yourself.

It's also possible, actually I should say likely as I believe I remember 
seeing gentoo/kde project discussion to that effect in either the overlay 
git logs or the project meeting reports, that either the profile or USE 
flag defaults just changed, and since you hadn't specifically set or 
unset the xinerama USE flag yourself, when the defaults changed, so did 
the behavior you got.  IOW, your versions of the above kde packages 
likely had the flag unset since you didn't set it, thus disabling xinerama 
support, but now that the default is to enable it, since it wasn't 
specifically disabled, you got xinerama support by default with the 
upgrade.

If that's the case, simply unchecking all five of the checkboxes in this 
kcm should return you to very nearly the same state (kwin-wise) as 
before, except that now you have the options exposed to toggle as you 
wish, while before they were hard-disabled (which you could do again by 
setting USE=-xinerama and doing an emerge --newuse @world or whatever).

That should take care of kwin, what about plasma?

Unfortunately, I don't know of any such kcm or other location options for 
plasma.  Thru 4.5, with xinerama enabled, plasma would create entirely 
separate activities for each enabled monitor (unless they were clone-
mode, of course, displaying the same thing on both monitors).  But as I 
said, multi-monitor support is evolving and becoming more fully featured, 
and 4.6 changed that, so they're separate backgrounds and can be set to 
separate layouts (desktop or folderview traditionally, search&launch or 
newspaper targeted at the smaller screen, typically netbooks and mobile 
devices, grouping and grid desktops as new options I'm not entirely sure 
about), but part of the same activity.

Note that I've always had USE=xinerama enabled here so I'm not sure of 
the USE=-xinerama behavior, but with USE=xinerama at least, at least 
early in 4.6, a new activity would come up as a single unified desktop 
initially, but as soon as changes were made, it'd split into the two 
separate ones as described above (which it had always been with 4.5 and 
previous, except for bugs, of course).

My reasonable guess, therefore, is that presently the only way to control 
plasma's multi-monitor behavior is with the xinerama USE flag.

So here's what I believe that flag does:  For the systemsetting package 
(kcontrol more accurately), it probably enables building that kcm.  For 
kwin, it enables the features controlled by that kcm.  For plasma-
workspace, it controls split vs. single unified layout, including both 
background and layout type.  (There's also ksplash but since that's only 
seen temporarily, it's not as important.)

Now that it's on, simply unchecking the appropriate options in the multi-
monitor kcm should get kwin back as you want it, but you'll probably have 
to rebuild plasma-workspace with USE=-xinerama to get it back to unified.

So the minimal change necessary to get back to where you were is to set -
xinerama for plasma-workspace in package.use and rebuild it, and uncheck 
the options in that kcm.  Restart kde after that, and you should be back 
where you were... I think.

Alternatively, set -xinerama in make.conf or individually for all three 
packages, and do an emerge --newuse @world.  (Do note that if you don't 
routinely use --newuse, you might have a backlog of quite a few unrelated 
packages that want to rebuild as well.  The usual advice applies... 
Always use --ask or --pretend first to avoid unexpected and unwanted 
surprises, and preferably, either put --newuse in EMERGE_DEFAULT_OPTS or 
use it regularly, in addition to the routine emerge --depclean and revdep-
rebuilds, thus helping to keep your Gentoo system free of nasty bug-
triggering cruft.)

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman