Problems with ni_pcimio & nvidia OpenGL graphics

Hi all,

I'm having some strange issues with taking data from the ni_pcimio comedi
driver, and plotting it on the screen in real-time with OpenGL.  I have three
systems and two daq cards.  The first system is a dual PII/450.  It has an
nVidia AGP video card, and an NI PCI daq card.  It runs RedHat 6.2, and 0.7.53
of comedi and 0.7.14 of comedilib.  It is rock solid -- I have no problems
with it.

Recently we got a bunch of Dell Dual Xeon 2.2Ghz systems, running RH7.2.
These also have nVidia cards.  I installed comedi-0.7.53 and comedilib-0.7.14
on one of these systems, and pulled the daq card out of the 6.2 system and put
it in the new Dell.  When I take samples from the card and draw them to the
screen, under certain conditions I will get an error from my call to

                ret = read(comedi_fileno(dev),buf,BUFSZ);

It seems to be related to what is drawn to the screen.  For example, I can
make read return an error by taking a window and dragging it over the plotting
windows, then removing it (forcing the plot to redraw itself).

Unfortunately, these two systems are completely different:

- different OS (and kernel)
- different processor
- different version of comedi

Finally, my last system is a Dell P4 2.2 GHz laptop.  The OS and comedi is
identical to the Dual Xeon system.  The graphics are nVidia.  I am using a
PCMCIA NI daq card, which also uses the ni_pcimio driver.  I have problems
similar to the Xeon with this system.

My next step will probably be to install RH7.2 on the older machine, and
verify that it is in fact a hardware problem.  However, I'm wondering if
anyone out there has experienced similar problems.  I'm fairly sure that they
are related to OpenGL and the nVidia driver.

Thanks for reading,

Jack

Received on 2002-07-19Z20:09:53