Emc vs modern lcd monitors

gene heskett gheskett at wdtv.com
Tue Aug 16 20:44:25 PDT 2011

On Tuesday, August 16, 2011 11:25:51 PM walter harms did opine:

> Am 16.08.2011 16:29, schrieb James Cloos:
> > Gene,
> > 
> > If the display gets in the way of the realtime code, you may want to
> > separate the two.
> > 
> > It may not be in vogue these days, but running X11 over tcp still
> > works.
> Just for your informations in several companies X11 is used for
> displaying. I used it the most time over tcp, see all the remote
> extension for X11. The problem are M$ user that have no idea about
> networking they tend to resort to several rather strange solutions.
> > An inexpensive laptop, a small fusion or atom box, a plug box will all
> > make reasonable graphics nodes.
> Hint:
> There is a small trap, you need to conf you XDM (or what you use) on the
> host to allow remote access.
> now you start on your notebook X -query <host> if everything works fine
> you will see the XDM from the host.
> re,
>  wh
> > If you boot the realtime box into text mode the display shouldn't get
> > in the way.  And you can always switch the monitor and keyboard over
> > should there be any problems booting.

That was one slim possibility I suppose, but since the gui is used on its 
own console 90% of the time so I can actually see what the machine is 
doing, not terribly practical.

But, I mad a totally amazing discovery this afternoon because while the 
vesa driver was generally acceptable, I was getting some "unexpected 
realtime delay" reports from RTAI on startup, 100% of the time.

At the behest of several on the emc mailing list, I made an edit to my 
xorg.conf on that box, from "vesa" to "ati".  The last time I tried that it 
was running the 8.xx LTS ubuntu install, and it was an unmitigated 
disaster, the graphics were slow, didn't follow what the machine was doing 
and in general unusable.

Today, it gave me a near perfect 1366x768 screen with absolutely square 
pixels, did not throw any real time errors at all, and it followed the 
machine precisely in real time.

So, to the folks that have been giving the radeon driver all that TLC it so 
badly needed when driving an ATI X1650 Pro card a year ago, a great big 


I expected the worst, and was dumb-founded, slack jawed, and amazed at the 
difference, it is now 100% usable.

The only bit of pickyness is that it now logs that it is getting an EDID 
read, to scanning available modes, wash rinse & repeat about 10-15 times at 
every startx.  It would boot X 20 seconds faster if that errant loop could 
be trimmed.  However, the way it works after the startup makes that time 
wasted into a very minor niggle.

I'm having some networking problems, related to trying to put a 802-11 
radio out there, so I can't just yet test another ssh -Y session.  With 
luck I might get that basket of rattlesnakes sorted tomorrow.

Cheers, gene
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