"No signal" on external monitor

dziambo · 2010-10-17 10:43:57

have toshiba tecra a11-11q. after hotplugging external monitor through vga, i have no signal message on that screen. xrandr:

Screen 0: minimum 320 x 200, current 2646 x 1024, maximum 8192 x 8192
VGA1 connected 1280x1024+1366+0 (normal left inverted right x axis y axis) 338mm x 270mm
   1280x1024      60.0*+   75.0  
   1280x960       75.0  
   1152x864       75.0  
   1024x768       75.1     70.1     60.0  
   832x624        74.6  
   800x600        72.2     75.0     60.3     56.2  
   640x480        72.8     75.0     66.7     60.0  
   720x400        70.1  
LVDS1 connected 1366x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1366x768       60.2*+
   1024x768       85.0     75.0     70.1     60.0  
   832x624        74.6  
   800x600        85.1     72.2     75.0     60.3     56.2  
   640x480        85.0     72.8     75.0     59.9  
   720x400        85.0  
   640x400        85.1  
   640x350        85.1

here everything seems to be fine. krandrtray also shows that external monitor is operative.

after rebooting computer both monitors work, but i can't change brightness on lvds.
i'm running archlinux, but the same results were on fedora, ubuntu and mint. there is no such problem on windows xp.
maybe it is not supported yet for Core Processor Integrated Graphics, but i couldn't find such information.

dziambo · 2010-10-26 21:30:03

anyone?

dziambo · 2010-11-28 16:59:39

maybe now?

pseudonomous · 2010-12-02 03:53:25

What happens if you connect the monitor and run:

xrandr --auto

?

dziambo · 2010-12-02 13:00:57

same results:

Screen 0: minimum 320 x 200, current 1366 x 1024, maximum 8192 x 8192
LVDS1 connected 1366x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1366x768       60.2*+
   1024x768       85.0     75.0     70.1     60.0  
   1024x768i      43.5  
   832x624        74.6  
   800x600        85.1     72.2     75.0     60.3     56.2  
   640x480        85.0     72.8     75.0     59.9  
   720x400        85.0  
   640x400        85.1  
   640x350        85.1  
VGA1 connected 1280x1024+0+0 (normal left inverted right x axis y axis) 376mm x 301mm
   1280x1024      60.0*+   75.0     72.0  
   1152x864       75.0  
   1024x768       75.1     70.1     60.0  
   832x624        74.6  
   800x600        72.2     75.0     60.3  
   640x480        72.8     75.0     66.7     60.0  
   720x400        70.1  
   640x350        70.1

external monitor becomes a copy of LVDS1(according to xrandr) but monitor's screen is still black.

pseudonomous · 2010-12-02 13:14:37

Perhaps xrandr is automatically trying to assign an unsupported mode to the monitor? If you know the supported resolutions with the monitor, trying manually passing the proper resolution to xrandr, for example if you know 1280x1024 is a supported mode do:

xrandr --output VGA1 --mode 1280x1024

in fact, if you haven't already tried it, you should probably just go through every supported mode and see what happens. Another thing to try would be using a different external monitor, see if this is a quirk specific to the monitor your using or if it occurs with other monitors as well.

delectate · 2010-12-02 13:20:06

what's your video card? i just tried nvidia videocard and vga output, different resolution,but it works

if you're using a nvidia videocard,you should try nvdia settings.

Last edited by delectate (2010-12-02 13:20:48)

pseudonomous · 2010-12-02 13:33:01

If I read the OP's post right, he has one of the on-die intel graphics processors.

dziambo · 2010-12-02 14:13:30

i have tried going through all these modes without success. maybe i wasn't clear in first post but after powering on laptop with connected external monitor, both screen work, bu i can't change brightness on laptop screen. i have tried connecting three different monitors with the same result. somehow os can't "wake up" the external screen.

steff · 2011-02-05 20:48:06

Exactly same behavior on Toshiba tecra a-8 and l-10, intel graphics.

R00KIE · 2011-02-06 14:23:29

Maybe it's a bios thing, try looking in the bios settings for the screen/output mode and try to configure it for internal display + external display.

steff · 2011-02-12 21:47:40

It is a bios issue, thanks: no power on VGA.
Setting "LCD and analog RGB" instead of "autodetect" resolvs.

dziambo · 2011-03-18 17:37:53

this option can be set in bios and toshiba hwsetup, right? then i don't have such choice. there is only "autoselect" and "internal LCD only".

olive · 2011-03-18 18:20:03

I have similar trouble with an intel 943GM chipset. From lspci:

00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev 03)

The workaround is to try to turn turn the external monitor on:

xrandr --output VGA1 --auto (nothing happens, except that xrandr believe VGA1 is on).

Then off

xrandr --output VGA1 --off

Now you can truly turn it on, for example with the following command or a more elaborate command for a dual screen setup:

xrandr --output VGA1 --auto

In my case (EI-system 3089), there is no bios setting related to the VGA output. I didn't had this problem with some previous version of xorg (or some component of which). But I do not remember exactly when this problem has appeared.

Last edited by olive (2011-03-18 18:21:12)

dziambo · 2011-03-18 19:27:22

olive wrote:

The workaround is to try to turn turn the external monitor on:
xrandr --output VGA1 --auto (nothing happens, except that xrandr believe VGA1 is on).
Then off
xrandr --output VGA1 --off
Now you can truly turn it on, for example with the following command or a more elaborate command for a dual screen setup:
xrandr --output VGA1 --auto

No, it doesn't work in my case.

zabotron · 2011-04-11 20:23:34

hi!
i've exactly the same problem on toshiba tecra a11. neither of your solution helped me.

IzidorM · 2011-06-27 20:10:32

I have Toshiba satellite pro u200 and I had the same problem. I had to change my bios settings, like ROKKIE wrote...

olive · 2011-07-02 14:06:15

Old thread sorry... Is it possible to delete this post?

Last edited by olive (2011-07-02 14:07:36)

Arch Linux

#1 2010-10-17 10:43:57

"No signal" on external monitor

#2 2010-10-26 21:30:03

Re: "No signal" on external monitor

#3 2010-11-28 16:59:39

Re: "No signal" on external monitor

#4 2010-12-02 03:53:25

Re: "No signal" on external monitor

#5 2010-12-02 13:00:57

Re: "No signal" on external monitor

#6 2010-12-02 13:14:37

Re: "No signal" on external monitor

#7 2010-12-02 13:20:06

Re: "No signal" on external monitor

#8 2010-12-02 13:33:01

Re: "No signal" on external monitor

#9 2010-12-02 14:13:30

Re: "No signal" on external monitor

#10 2011-02-05 20:48:06

Re: "No signal" on external monitor

#11 2011-02-06 14:23:29

Re: "No signal" on external monitor

#12 2011-02-12 21:47:40

Re: "No signal" on external monitor

#13 2011-03-18 17:37:53

Re: "No signal" on external monitor

#14 2011-03-18 18:20:03

Re: "No signal" on external monitor

#15 2011-03-18 19:27:22

Re: "No signal" on external monitor

#16 2011-04-11 20:23:34

Re: "No signal" on external monitor

#17 2011-06-27 20:10:32

Re: "No signal" on external monitor

#18 2011-07-02 14:06:15

Re: "No signal" on external monitor

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