trinity-users@lists.pearsoncomputing.net

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Month: December 2015

Re: [trinity-users] Configuring two monitors connected to the same computer

From: Felix Miata <mrmazda@...>
Date: Wed, 23 Dec 2015 16:24:24 -0500
Ken Heard composed on 2015-12-23 22:44 (UTC+0700):

> Felix Miata wrote:

>> Ken Heard composed on 2015-12-22 15:22 (UTC+0700):
 
>>> I have a box with Debian Wheezy and TDE installed in it.

> This is my parentboard:
> http://www.gigabyte.com/products/product-page.aspx?pid=4600#ov
 
> Output of lspci:
> 00:02.0 VGA compatible controller: Intel Corporation Haswell Integrated Graphics Controller (rev 06)

Mine reads slightly differently, but I doubt there's any functional difference:
00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller (rev 06)

>> Can't say for sure why, but based on my experience, it should be a 
>> surmountable problem. Possibly HDCP is affecting behavior, or the
>> HDMI cable. Have you tried any other cables? Cheaper HDMI cables
>> are often a cause of otherwise inexplicable trouble.
 
> It is a 1.4a HDMI cable 10 m long.

This is potentially an obstacle. Do a little research to understand:
https://www.google.com/search?q=hdmi+cable+length
 
>> What's likely to be happening here is that the TV does not support
>> the lower 1600x900 mode that Xorg automatically uses without being
>> told otherwise for the larger resolution screen, so both falls back
>> to a lower mode, and displays that mode without stretching,
>> confining to the pixels on the 1920x1080 screen matching the actual
>> mode used. If there is a video mode dictated on the kernel's
>> cmdline (from bootloader), Xorg could be using it, as the Intel
>> driver will do so unless told by xrandr or xorg.conf* to do 
>> otherwise.

> I have never used xrandr; and

Needing it is a bit of a nuisance. Most people with single displays
will never need it. Often it's the only way as a practical matter a
multiple display user can achieve desired results. Use the URL I previously
provided (...setup) as a guide to some possibilities. Only any single line
in it should ever be used, but having them all as comments facilitates
quick switching among possibilities in whilst testing by simply uncommenting
any single line desired.

> there is no xorg.conf anywhere in my box.

Most people never need them. Automagic made them optional, typically for
overriding unwanted automagic. Any who need one as an alternative to xrandr
must create it. Some DEs have built-in tools that either create one, or
operated as an alternative to one. AFAICT, TDE is not one of them. NVidia
users using proprietary drivers get a tool to create one automatically.
Intel and other FOSS driver users must either create one manually, or copy
one from somewhere, into /etc/X11/.

Various URLs that may help in constructing your own xorg.conf*:
https://01.org/linuxgraphics/documentation/how-set-dual-head-intel-graphics-randr-1.2
https://wiki.gentoo.org/wiki/Xorg.conf
https://wiki.gentoo.org/wiki/Xorg/Multihead
http://www.thinkwiki.org/wiki/Xorg_RandR_1.2
https://wiki.archlinux.org/index.php/Multihead
 
> cat /proc/cmdline returns the following:
> BOOT_IMAGE=/vmlinuz-3.16.0-0.bpo.4-amd64 root=UUID=056f8d50-7958-4655-bfa6-39b5d03f0b03 ro quiet

OK, so cmdline is providing no interference with Xorg operation. If you want
a more informative boot process you can remove "quiet" from /etc/default/grub.
Then on next boot reconfig (e.g. new kernel), it will be removed from grub.cfg,
changing the look of your boot process.

> What seems to me to be relevant in /var/log/Xorg.0.log follows.
> [    57.306] Current Operating System: Linux TH 3.16.0-0.bpo.4-amd64 #1 SMP Debian 3.16.7-ckt11-1+deb8u6~bpo70+1 (2015-11-11) x86_64

This is equivalent to running 'uname -a'.

> [    57.306] Kernel command line: BOOT_IMAGE=/vmlinuz-3.16.0-0.bpo.4-amd64 root=UUID=056f8d50-7958-4655-bfa6-39b5d03f0b03 ro quiet

You said you couldn't find it, but here it is. :-)

> [    57.318] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
> [    57.398] (==) No Layout section.  Using the first Screen section.
> [    57.398] (==) No screen section available. Using defaults.
> [    57.398] (**) |-->Screen "Default Screen Section" (0)
> [    57.398] (**) |   |-->Monitor "<default monitor>"
> [    57.398] (==) No monitor specified for screen "Default Screen Section".
> 	Using a default monitor configuration.

All this is simply informing it's operating via automagic rather than having
found an xorg.conf. More relevant is the output you'll see if you run the script
I pointed you to, in particular, lines containing "Output", "connected" and/or
"using initial mode". They tell you the output names of your video connectors
that are required to design working xrandr commands or xorg.conf elements.
-- 
"The wise are known for their understanding, and pleasant
words are persuasive." Proverbs 16:21 (New Living Translation)

 Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!

Felix Miata  ***  http://fm.no-ip.com/