Request help configuring X11

Tony0945 · Posted: Thu May 07, 2015 8:29 pm Post subject: Request help configuring X11

I had a Hyundai Imagequest CRT monitor (actually still have it) and switched to a used Viewsonic flat panel. X11 wants to drive it at 75Hz, apparently thinking that the CRT is still there. This causes the flat panel to hiss and flicker on and off. The Flat Panel works fine when connected to a Windows computer, so hardware is not the problem.

I tried to enter a modeline into /etc/X11/xorg.conf.d/40-monitor.conf, following the wiki: https://wiki.gentoo.org/wiki/Xorg/Guide#The_xorg.conf.d_directory

Here is the configuration file.

DONAHUE · Posted: Fri May 08, 2015 7:11 pm Post subject:

Presuming use of open source video driver, suggest have only the flat panel connected, then:

Tony0945 · Posted: Sun May 10, 2015 11:28 pm Post subject:

Didn't do anything except make it worse. The monitor won't stay on long enough to select the auto-adjust.

I dismantled the monitor looking for bulging capacitors as i see all over the internet. Caps look fine. Now I'll throw away the monitor and buy another. It seems like I have to find a 75Hz monitor.

Letharion · Veteran Joined: 13 Jun 2005 Posts: 1344 Location: Sweden

This is surprising, the last time I can remember needing to manually configure X like this must be 5 years ago or so, and even then that was because it was a unusual multi GPU setup where one card drove the display and the others were running Cuda apps.

For anything that even resembles a "common" setup, I'd completely expect DONAHUE's suggestion above to "just work".

In the xorg log you have

Jaglover · Posted: Mon May 11, 2015 12:25 pm Post subject:

I had a box with nVidia blob. The combination card/driver did not work properly, although was supported. As a result EDID wasn't pulled from monitor and X defaulted to a wrong mode, causing monitor to flicker. Had to save EDID into a binary file and feed it to X.
_________________
My Gentoo installation notes.
Please learn how to denote units correctly!

krinn · Watchman Joined: 02 May 2003 Posts: 7470

You can attach "Monitor" to "Screen" or "Device"
You attach "Device" to "Screen"
Than you attach "Screen" to "ServerLayout"

Tony0945 · Posted: Fri May 15, 2015 12:11 am Post subject:

Wow, don't know where to start acknowledging this fine help. First let me apologize for my late response. I've been preparing for a trip.

I followed Lotharion's link and emerged read_edid. Unfortunately it doesn't recognize any monitor including two quite new Samsung's. However, it did get me thinking about how X11 recognizes a monitor with no configuration. There must be some interrogation like read_edid to recover the information from the monitor itself. Else, why does Mate show the Samsung monitors as "Samsung 22"" since I never told X about the Samsung's and they are detected without a configuration file. I had made the configuration file for the Hyundai many years ago because it was not recognized. At that time Fedora had instructions as to how to write a configuration file. I've been running Gentoo for about nine years so that was long ago indeed.

I also found this handy calculator which works: http://www.arachnoid.com/modelines/

I had already dismantled the Viewsonic, which was reported as "Unknown monitor" before I attempted to configure a file, so I connected a old 17" square Dell that a friend gave me. With no conf files at all it was detected as a Dell and came up with no problem. However, the Dell does support 75Hz which the Viewsonic does not.

Viewsonic used to be a good brand in the CRT days. When I got this one apart, all the interior parts were labeled "Hannes-G" rather than "Viewsonic". I said capacitors looked OK, but on a closer look, I see slight convexity, although no leaking. The capacitors are CapXcon which are supposed to be problematic. The monitor was made in 2005 and is a Viewsonic VA912b. Now, I have to decide if I want to spend $11 buying a capacitor kit and soldering the caps (or more likely sweet talk my daughter into doing it, I haven't soldered for a decade and my eyes and hands are a lot worse) or just junking it and buying another used Dell. I never thought much of Dell but this used business monitor works and that's all I neeed for a mostly headless machine. I went this LCD route to avoid leaving the Hyundai powered up all the time (the machine is my main file server).

Many thanks to Krinn. I did set up a configuration for the Dell after it was auto-detected using his post, the aforementioned modeline calculator and xrandr info.

Unfortunately, I only have a hazy idea why this worked. Another machine that runs mythtv has an nvidia card that also has analog outputs and s-video. I had planned to connect this to an older analog TV for a bigger picture. I'd like to figure out how to set that up. X can't auto-detect a dumb TV can it?