Re: Problems with ni_pcimio & nvidia OpenGL graphics

A thousand blessings upon your family!!  =)  It was indeed an I/O error, and
indeed, I cranked the buffer size up a notch and everything is suddenly
hunky-dory.  Thanks very much,

Jack

On Fri, Jul 19, 2002 at 04:50:10PM -0700, David Schleef wrote:
> On Fri, Jul 19, 2002 at 02:09:53PM -0700, Jack Culpepper wrote:
> > 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);
> 
> In 0.7.65, read() will return -1 and set errno to ESPIPE (broken pipe)
> if there is a board-level problem, like a hardware FIFO overflow.  It
> will set errno to EIO (I/O error) if it's a Comedi buffer overflow.
> The latter is easier to correct -- just make your Comedi buffer
> larger (man comedi_config).  However, it may be wise to figure out
> where your app is spending it's time instead of reading the data from
> the Comedi device.
> 
> Also note that some window managers have the nasty habit of freezing
> the X display when resizing windows.  So, if you read from Comedi and
> make Xlib function calls in the same thread, you may get stuck in
> Xlib for several seconds while some other window is being resized.
> Bad.
> 
> 
> 
> dave...
>

Received on 2002-07-19Z23:12:56