USBDUX fast

Hi List,

I have a problem with the USBDUX-fast comedi driver (or the USBDUX-fast
firmware?). I use Kernel 2.6.19.7 with RTAI 3.5 and RTAI-enabled Comedi
from CVS:

When using a comedi command for acquisition, I get the last half
of the received data zero padded on many reads. Sometimes the read
operation returns only zeroes. Nevertheless, the data rate
corresponds to the sampling interval which was defined by the
comedi command. Sometimes I can reduce this effect by selecting
a proper timing between the reads or between the first read and
the subsequent reads. But it is hard to eliminate this effect
completely. The effect is more moderate if I wait for some time
between the first and the subsequent reads. To read the data I
use: read(comedi_fileno(dev),(unsigned char*)buffer,
comedi_get_buffer_contents(dev,subdevice))). If I first do a
comedi_get_buffer_contents and then wait a little and read with
the previously obtained buffer size, the effect is the same.

Do other people have the same problem and is there a known workaround or
even a fix to this? Thanks for your time. 

Best Regards
Georg

Received on 2007-06-07Z07:21:49