Ubuntu/Gnome locking up after fresh install

This is mostly to hopefully save others the pain that I went through trying to get Ubuntu 10.4 with EMC installed and running.

Basically the problem I encountered was not being able to login in with a normal Gnome seesion after I downloaded and installed the Ubuntu 10.4/EMC package from the LinuxCNC.org site.

Here is my post over at the Ubuntu forums where I documented my problem looking for help and the subsequent resolution I found:
ubuntuforums.org/showthread.php?t=1615270

To summarize, I am using an older machine for my CNC project which had a Matrox G550 video card. It appears that a component of Ubuntu 10.4 called AIGLX doesn't support a number of older video cards (see links in my Ubuntu forum post). By turning AIGLX off I was able to log in to a normal Ubuntu Gnome session. Turning it off meant adding to my /etc/X11/xorg.conf file the following (from the replies in the bug report):

Section "ServerFlags"
Option "AIGLX" "off"
EndSection


Note that you may have to create the xorg.conf file as it apparently is not created by default in Ubuntu 10.4 (it is generally no longer needed although it will be used if it exists).

Hope this is useful.

Ray

Ray,

Thanks for the post I am sure the info will be helpful.
Are you still restricted to 800x600?
Why did you decide on 10.04 instead of 8.04?
Did you also try to install with 8.04 which may work better with older hardware?

Rick G

So far, yes still stuck at 800x600. I think I'm still having problems with the video which seems to be causing EMC to hang on any of the Axis sims (I haven't finished building my actual cnc machine yet).

As for going with v10.04 instead of v8, didn't really think too much about it. My machine isn't that old (I can still find the motherboard, processor and video card available online from a few sources) and I also figured that general support for Ubuntu would be better for 10.04 (and the Ubuntu site indicated my h/w should be fine but I'm starting to question that now).

I haven't gotten into the cad/cam software side yet either and figured I'd have better luck with a more recent version of the OS.

I'm also playing with another project doing some parallel port control (separate machine) with a friend and wanted to use Ubuntu 10.04 so I figured it would be easier to stay consistent rather than trying to confuse myself with different versions of the OS.

DO you think I'd be better going with the older OS/EMC setup? Any suggestions for the CAD/CAM s/w in open source Ubuntu/linux (or mac as that is my normal machine)?

Just a quick additional note. I decided to try 8.04 this morning to see if it 'just works'. The install went ok and Ubuntu seems fine but it still leaves me in 800x600 video and v8 doesn't seem to allow me to use my wireless card (a wireless connection set up isn't obvious in the network connections setup).

EMC also locks the machine on an Axis sim - the emc splash screen appears but then the video looses cohesion (hard to describe but it's like random vertical lines sliding out of sync with the rest of the display) and the computer becomes unresponsive. A hard reset seems to be the only way out.

I'll have to think about where I'm going to go from here. Any suggestions?

Ray,

Have you looked at this, especially the DISPLAY section?
wiki.linuxcnc.org/emcinfo.pl?TroubleShooting

Yes those are all good reasons to try 10.04 I only mention 8.04 because I have several machines running emc2 and some are fine on 8.04 but will not work on 10.04 and some test better with 10.04.
I wanted to try HEEKS but it appears to not work on 8.04 so I thought I would try 10.04, picked the wrong machine:(

Rick G

Rick,

No, I hadn't found that troubleshooting section but I'll look at it in a bit and see if I can sort out my emc troubles.

I have, however, solved my video resolution problems. It appears the mga drivers that come with Ubuntu 10.04 tries to query the video card and then set the appropriate video options. It's piss poor at it though and ends up defaulting to a maximum of 800x600 with a 60Hz refresh rate. The solution was to get the correct options set in the xorg.conf file and force mga to use those. I will be documenting my troubles in the Ubuntu forums thread I started after work today (as much for myself as for others).

Rick & Andy,

I also found an article on HeeksCAD in the Fall issue of Digital Machinist at the bookstore yesterday and it looks promising. I will probably give that a go once I get this amd/ubuntu machine running emc properly.

Thanks for the suggestions,
Ray

Rick,

I've started going through the troubleshooting section you linked to but no real success so far. Do you or anyone else know how up to date that documentation is? It only seems to mention hardy heron or dapper drake.

Also it also suggests using the vesa display drivers whereas I've got the mga drivers working. Some of the info I've stumbled across in my travels implies I should be able to get the vesa drivers to work but I'm wondering if there is a reason to use one over the other.

Going through the troubleshooting guide, I was able to get the real time system to start and stop from a terminal window. The messages in the log seem to show it starts and stops fine.

I did find a couple of the rt files missing as listed.neither the RTAI_SHM or it's lower case link file rtai_shm existed so I created them. The /dev/rtc file also was a bit different. The /dev/rtc file was actually a link to a /dev/rtc0 file (which was already there). I didn't think that should make a difference so I didn't touch those. The only difference these changes seemed to make was to garble the screen even more on an EMC startup with an axis sim profile. Note that before this change, i also noticed that emc wasn't always garbling the screen on an axis sim startup. Sometimes it would just lock up the computer after it displayed the emc splash screen, a small window down in the bottom right corner and the main interface window behind the splash screen (they would come up in that order I think).

The realtime latency test script also ran although some of the numbers in the lat avg, lat max and ovl max columns were negative. I'm not sure what that means. And I'm not sure where the BASE_PERIOD setting is that I should be comparing it to.

One last note. Being a bit rusty on my unix environment stuff, I'm not sure where to look for some type of error message log that emc might spit out. So far, whenever emc hangs and I hit the reset button to restart, i can't find any error messages(or even 'emc starting up' type messages) through the log viewer. Is there a particular place to look for something like that?

Thanks for any help anyone can provide me.
Ray

So being impatient and finding out I was suddenly free today I decided to fiddle a bit more and made a bit of progress.

I noticed the 'axis locking up thread' in the AXIS and decided to try the vesa driver instead of the mga driver. That seems to have solved my locking up problem as well.

So far, however, my display is limited to 1024x768 (instead of 1280x1024) which is workable. The settings in the modeline line in the xorg.conf file don't seem to have any effect and in fact the vesa driver initially set my refresh rate too high (85Hz I think). Oddly, my monitor complained by putting it's own floating window with a 'refresh out range' message but still allowed me to see the login and desktop behind it.

The only way to get it down to the max of 75Hz that my monitor can take seemed to be to set 75 Hz as the maximum vertical refresh rate in the monitor section.