DPC

I have a situation where I can run my Flex-1500 for as much as a day, and then it freezes the waterfall. Sometimes this happens after only a few minutes, but usually, after having cleaned up the system over the past several days, I manage to get at least a few hours of runtime.

Exiting PSDR, then restarting, shows a bizarre solid yellow waterfall pattern. Exiting again, and power-cycling the Flex-1500 fails to restore the FLEX-1500 Software Defined Radio device driver, while the FlexRadio USB Kernel Driver remains intact. And then a few seconds later I get a consistent BSOD claiming the Flex driver had an IRQ less_or_equal -- whatever that means.

So I tried my best to track down the dreaded DPC's, and now I have a bizarre effect of consistently high latencies, measured with DPC Latency Checker, measuring on average, between 1600-1800 usec, peaking at times to around 4 ms. This is with nothing running !!

Now, if that isn't bizarre enough, I can still fire up PSDR and have it piping the I&Q channels at 48 kHz sample rate into VAC. Then when I fire up CWSkimmer feeding off the VAC the DPC latencies magically drop to a pretty consistent 100-200 usec !!!

So, how can running all this interrupt laden stuff actually be improving my system performance? As soon as I quit CWSkimmer the DPC latency shoots consistently skyward again. Could this be related to VAC?

When I run the detailed Latency Checker looking at drivers involved, the NVidia video display driver always tops the list. I have gone through the device manager and disabled just about everything - except - the video driver. Can't very well see what I'm doing if I disable it.

73 de Dave, N7AIG