FreeBSD 11.1, Xfce, and laptop screen and external monitor resolution

Polytropon freebsd at edvax.de
Wed Aug 2 05:48:13 UTC 2017


On Tue, 1 Aug 2017 21:48:46 -0700, David Christensen wrote:
> On 07/30/17 21:18, Polytropon wrote:
> > On Sun, 30 Jul 2017 19:30:01 -0700, David Christensen wrote:
> >> When I run 'startxfce4', Xfce starts with a resolution of 1024x768.
> >> Applications Menu -> Settings -> Display offers two choices: 1024x768
> >> and 800x600.  How do I set the Xfce resolution to 1280x800 when driving
> >> the laptop screen?
> >
> > Option 1 is to set it using a configuration file "snippet" in the
> > /usr/local/etc/X11/xorg.conf.d directory,
> >
> > xorg.conf: only put section "Screen", subsection "Display",
> > setting "Modes" with the screen size you want.
> >
> > For example, it could look like this:
> >
> > 	Section "Screen"
> > 		Identifier	"Screen0"
> > 		Device		"Card0"
> > 		Monitor		"Monitor0"
> > 		DefaultDepth	24
> > 	        SubSection "Display"
> > 			Viewport	0 0
> > 			Depth		24
> > 			Visual		"TrueColor"
> > 			Modes           "1920x1080" "1280x800"
> > 	        EndSubSection
> > 	EndSection
> 
> The X.org driver is supposed to read the EDID information for all 
> available displays and act upon it "correctly"; this is not happening.

Yes, it is supposed to do so, but in some cases, it strangely
does not work. This is where "forced settings" can be used to
tell X the correct settings it won't detect on its own.



> I did some testing using FreeBSD 11.0 -- EDID works.  But if I attempt 
> to run in dual-head mode, I get the same bug as FreeBSD 11.1 where 
> windows and dialogs are mostly blacked out.

Hmmm... I've never tried using dual-head mode (independent
displays?) in this way. Having both displays active, while
the bigger one simply scales up the content of the smaller
one, is possible.



> > You could then probably even use Ctrl+Alt+[+] and Ctrl+Alt+[-]
> > to switch between the two modes (not tested, but old-fashioned
> > X could do that).
> 
> Yes, I'm finding that I need old-school tricks.

You need them whenever "modern magic" doesn't work. ;-)



> > Option 2 is to use xrandr in ~/.xinitrc with the --size
> > option.
> 
> This is 2017 and I shouldn't have to mess with low-level X stuff. 

Fully correct, but for testing it's very convenient, and in case
the mentioned autodetection does not work as intended, it can
provide a useful workaround. You could even program two xrandr
calls to function keys for easily switching between "big" and
"small" screen.

However, as you said, it _should_ work as it is supposed to do,
so it's totally valid to assume a bug here - or simply incomplete
software support...


-- 
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...


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