[hpsdr] Recent PowerSDR versions and DPCs - curiouser andcuriouser!!

[Mike Stevenson]

Hi Peter

Yes I am also see the effect you describe.
Also sometimes at powerup of the hardware and during use, I have also had 
the received audio go distorted.
Repowering the hardware clears the problem.
The problem is more likely to occur when starting other software.
CPU i7, Windows 7 64bit. PowerSDR 2.2.3 10/19/12

This was not see in earlier versions of PowerSDR even when running other 
software at the same time.

Mike G8ALS

-----Original Message----- 
From: PETER BUCK
Sent: Monday, October 22, 2012 7:55 PM
To: hpsdr at lists.openhpsdr.org
Subject: [hpsdr] Recent PowerSDR versions and DPCs - curiouser 
andcuriouser!!

***** High Performance Software Defined Radio Discussion List *****

Hello All,
I have been wondering for some time if anyone else who uses PowerSDR 
regularly has the following issues. My setup is Mercury, Pennylane, Metis, 
Alex, Pennywhistle and Excaliber with current firmware and PowerSDR dated 
10/16/12. Computers are an older dual-core E6750 2.6MHz, and a dual-core 
mini-itx also 2.6MHz. Both have 4MB RAM and run XP. I have run dpclat while 
operating with either computer, and both systems show the same weird 
behaviour. With the display set as panafall, at irregular time intervals 
sometimes up to several hours, the panascope display freezes and 
receive/transmit audio drops out. As far as I can recall, this issue did not 
arise with versions of PowerSDR in use over a year or so ago.
As expected, dpclat revealed a huge (off scale) dpc peak when this freeze 
occurred. Sequentially killing unused drivers had no effect, but if PowerSDR 
was not running, these huge peaks never occurred. With PowerSDR running 
normally, the typical dpc was about 50microsec, rising sometimes to about 
1000microsec for short periods after band change and/or mode change. Even so 
such changes did not give rise to significant clicks and bangs in the Rx 
audio or display jitters. However, sometimes when PowerSDR was started, or 
after a band change, especially in USB/LSB mode, dpcs would rise to 
some15000microsec and stay there. Normal operation could continue in this 
state, but I suspect that any additional polling while in this state could 
trigger the freeze-up. Band and mode changes when in this state were usually 
accompanied by audio clicks and bangs, and were much slower than normal.
Unfortunately these problems are not 100% replicable, but are annoying none 
the less. Is it possible there is an odd bug lurking either in the driver, 
or in the bandswitch/mode switch parts of the PowerSDR code? - or do I 
simply need to upgrade my computer?
I have also noted the recent change in behaviour of the bandswitches when 
saving last used frequency which was raised recently.
Pete, G3LWT
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