[ltp] T520 Ubuntu 11.10 x64 - can't connect external monitor
Fen Labalme
linux-thinkpad@linux-thinkpad.org
Mon, 6 Feb 2012 17:20:04 -0500
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On Sun, Feb 5, 2012 at 9:50 PM, Marius Gedminas <marius@gedmin.as> wrote:
> On Sun, Feb 05, 2012 at 12:47:42PM -0500, Fen Labalme wrote:
> > 2012/2/4 Marius Gedminas <marius@gedmin.as>
> > >
> > > > Will the VGA be able to drive a 1920x1200 display?
> > >
> > > Why not? My Asus EeePC 900 (ancient Intel 945) drives a 1920x1080p TV
> > > over VGA with sufficient 3D for all those Compiz effects.
>
I have been running my monitor (Samsung Syncmaster T260) from DVI until now
and it was working fine, so I was suspicious of the analog input. But I
just checked it's specs and it should display 1920x1200 using a VGA cable
just fine.
> I dropped back to running with BIOS set to Intel Integrated Graphics and
> > was able to get a 3200x1200 virtual display with the external monitor
> > attached via a VGA cable (and hotplug basically works):
> > 1600x900 (T520) + 1600x1200 (Samsung) = 3,840,000 pixels total
> >
> > This is lower than the native (1920x1200) resolution on Samsung (and
> looks
> > horrible).
>
> Do you know why this is?
>
No, actually. When I use 'Displays...' to set the Syncmaster's width to
1920, xrand reports exverything as it should be:
> xrandr
Screen 0: minimum 320 x 200, current 3520 x 1200, maximum 8192 x 8192
LVDS1 connected 1600x900+0+0 (normal left inverted right x axis y axis)
345mm x 194mm
1600x900 60.0*+ 50.0
...
VGA1 connected 1920x1200+1600+0 (normal left inverted right x axis y axis)
550mm x 343mm
1920x1200 60.0*+
...
...but the Samsung only displays 1600 bits wide. (There are black 'dead
zones' on either side that the cursor needs to traverse to get to the edge
or other monitor.)
What if you tried to arrange the monitors one above the other instead of
> side by side? What if you disabled the internal display and used only
> VGA out -- could you use 1920x1200 then?
>
Excellent idea, but unfortunately the Samsung will still only display 1600
pixels wide.
> Question 1: Am I thinking about this right? Do those numbers confirm that
> > I can't get a virtual screen the size I want using only one or the other
> > GPU?
>
> No, those numbers don't limit the virtual desktop size, just the size of
> each screen.
>
Hmmm... From the xrandr output above, it suggests I have just one screen of
3520 x 1200 (= 4,224,000 pixels) which is bigger than the reported max
resolution of the Intel HD 3000 GPU (2560 x 1600 = 4,096,000 pixels).
But unfortunately, even when I placed the T520 screen above or below the
Syncmaster, resulting in a combined size of 2100 x 1920 (= 4,032,000
pixels) which is less than the advertised max of the GPU, the darn monitor
still only displayed 1600 wide.
> (BTW: I had to remove the xorg.conf during the switch from Discrete to
> > Integrated graphics, and even after fooling with the setup a while, no
> new
> > xorg.conf file was created.)
>
> Right, that's normal. The open world of Linux graphics has progressed
> to the point where almost everything is autodetectable, hotpluggable,
> and configurable at runtime, so Xorg.conf is rarely needed.
>
I'm beginning to think I might need to create an xorg.conf to force the
screen size. And I've seen some posts suggesting to share the load between
the intel and nvidia GPUs -- I tried this for a while over the weekend but
was not able to get things working. Unfortunately for both these cases,
I'm not fluent in xorg.conf.
Marius Gedminas
>
Thanks again for your continuing help and encouragement.
=Fen
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On Sun, Feb 5, 2012 at 9:50 PM, Marius Gedminas <span dir=3D"ltr"><<a hr=
ef=3D"mailto:marius@gedmin.as">marius@gedmin.as</a>></span> wrote:<br><d=
iv class=3D"gmail_quote"><blockquote class=3D"gmail_quote" style=3D"margin:=
0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class=3D"im">On Sun, Feb 05, 2012 at 12:47:42PM -0500, Fen Labalme wro=
te:<br>
> 2012/2/4 Marius Gedminas <<a href=3D"mailto:marius@gedmin.as">mariu=
s@gedmin.as</a>><br>
> ><br>
> > > Will the VGA be able to drive a 1920x1200 display?<br>
> ><br>
> > Why not? =A0My Asus EeePC 900 (ancient Intel 945) drives a 1920x1=
080p TV<br>
> > over VGA with sufficient 3D for all those Compiz effects.<br></di=
v></blockquote><div><br></div><div>I have been running my monitor (Samsung =
Syncmaster T260) from DVI until now and it was working fine, so I was suspi=
cious of the analog input. =A0But I just checked it's specs and it shou=
ld display 1920x1200 using a VGA cable just fine.</div>
<div><br></div><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex=
;border-left:1px #ccc solid;padding-left:1ex"><div class=3D"im">> I drop=
ped back to running with BIOS set to Intel Integrated Graphics and<br>
> was able to get a 3200x1200 virtual display with the external monitor<=
br>
> attached via a VGA cable (and hotplug basically works):<br>
> 1600x900 (T520) + 1600x1200 (Samsung) =3D 3,840,000 pixels total<br>
><br>
> This is lower than the native (1920x1200) resolution on Samsung (and l=
ooks<br>
> horrible).<br>
<br>
</div>Do you know why this is?<br></blockquote><div><br></div><div>No, actu=
ally. =A0When I use 'Displays...' to set the Syncmaster's width=
to 1920, xrand reports exverything as it should be:</div><div><br></div>
<div>> xrandr</div><div><div>Screen 0: minimum 320 x 200, current 3520 x=
1200, maximum 8192 x 8192</div><div>LVDS1 connected 1600x900+0+0 (normal l=
eft inverted right x axis y axis) 345mm x 194mm</div><div>=A0 =A01600x900 =
=A0 =A0 =A0 60.0*+ =A0 50.0 =A0</div>
<div>=A0 =A0 ...</div><div>VGA1 connected 1920x1200+1600+0 (normal left inv=
erted right x axis y axis) 550mm x 343mm</div><div>=A0 =A01920x1200 =A0 =A0=
=A060.0*+</div></div><div>=A0 =A0 ...</div><div><br></div><div>...but the =
Samsung only displays 1600 bits wide. =A0(There are black 'dead zones&#=
39; on either side that the cursor needs to traverse to get to the edge or =
other monitor.)</div>
<div><br></div><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex=
;border-left:1px #ccc solid;padding-left:1ex">What if you tried to arrange =
the monitors one above the other instead of<br>
side by side? =A0What if you disabled the internal display and used only<br=
>
VGA out -- could you use 1920x1200 then?<br></blockquote><div><br></div><di=
v>Excellent idea, but unfortunately the Samsung will still only display 160=
0 pixels wide.</div><div><br></div><blockquote class=3D"gmail_quote" style=
=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class=3D"im">> Question 1: Am I thinking about this right? =A0Do th=
ose numbers confirm that</div><div class=3D"im">
> I can't get a virtual screen the size I want using only one or the=
other<br>
> GPU?<br>
<br>
</div>No, those numbers don't limit the virtual desktop size, just the =
size of<br>
each screen.<br></blockquote><div><br></div><div>Hmmm... From the xrandr ou=
tput above, it suggests I have just one screen of 3520 x 1200 (=3D 4,224,00=
0 pixels) which is bigger than the reported max resolution of the Intel HD =
3000 GPU (2560 x 1600 =3D 4,096,000 pixels).</div>
<div><br></div><div>But unfortunately, even when I placed the T520 screen a=
bove or below the Syncmaster, resulting in a combined size of 2100 x 1920 (=
=3D 4,032,000 pixels) which is less than the advertised max of the GPU, the=
darn monitor still only displayed 1600 wide.</div>
<div><br></div><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex=
;border-left:1px #ccc solid;padding-left:1ex"><div class=3D"im">
> (BTW: I had to remove the xorg.conf during the switch from Discrete to=
<br>
> Integrated graphics, and even after fooling with the setup a while, no=
new<br>
> xorg.conf file was created.)<br>
<br>
</div>Right, that's normal. =A0The open world of Linux graphics has pro=
gressed<br>
to the point where almost everything is autodetectable, hotpluggable,<br>
and configurable at runtime, so Xorg.conf is rarely needed.<br></blockquote=
><div><br></div><div>I'm beginning to think I might need to create an x=
org.conf to force the screen size. =A0And I've seen some posts suggesti=
ng to share the load between the intel and nvidia GPUs -- I tried this for =
a while over the weekend but was not able to get things working. =A0Unfortu=
nately for both these cases, I'm not fluent in xorg.conf.</div>
<div><br></div><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex=
;border-left:1px #ccc solid;padding-left:1ex"><div class=3D"HOEnZb"><div cl=
ass=3D"h5"><span style=3D"color:rgb(136,136,136)">Marius Gedminas</span>=A0=
</div></div>
</blockquote><div><br></div><div>Thanks again for your continuing help and =
encouragement.</div><div>=3DFen=A0</div></div>
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