Re: rt20 patch question

From: Steven Rostedt
Date: Wed May 10 2006 - 12:17:03 EST



Wow! I asked for some info on your system, and boy, did I get info! :)

On Wed, 10 May 2006, Mark Hounschell wrote:

>
> Ok, I'll try to explain the application. It is an emulation of some old
> legacy hardware (SEL-32) that ran a proprietary RTOS (MPX-32). We
> emulate the hardware not the software. We have some specialized pci
> cards that emulate some of that hardware. IE, a card that has some
> timers and external interrupt capabilities (RTOM). All our drivers are
> GPL BTW.
>

[snip long explaination of system]

>
> So to my problem. What I mean by "the machine stops" is just that all
> indications of the mouse, keyboard, and vidio stop. Then in a few
> seconds will usually continue. At first I only saw problems when using
> ethernet in the emulation. I would telnet into the emulation from the
> linux box and do the equivalent of cat'ing a very large file. The
> machine will always "stop" somewhere randomly along the display. Then
> maybe continue on or maybe not. So I thought I might have a problem with
> my ethernet module. Then I noticed similar things with the SCSI module
> when accessing legacy scsi devices from within the emulation. Somtimes
> the whole machine doesn't stop. It would appear that only somethings
> have stopped. Like one or more of my I/O threads??
>
> I can only say for sure that I do not have these "stops" when running
> any other kernel or when running the rt20 kernel in any of the
> non-complete preemption modes.
>
> The only change that had to be made to this app for it to run at all on
> the rt20 kernel was insuring that the RTOM irq thread was at a higher
> priority than the CPU process/thread. Otherwise no signals were received
> from the RTOM.
>

Well, I need to leave the office tonight. I'll look at it in my hotel,
and tomorrow, I'll give some feedback.

Thanks,

-- Steve

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