Re: [Discuss-gnuradio] PCI-DAS4020/12 problem roundup

[Sérgio Rui Silva]

>Is every one who's having the problem running gcc 3.3?

I'm running Linux Kernel 2.4.21 and GCC 3.2.2 and I found
problems using the MC4020 board.

>Can one of you folks who's having the problem, reproduce this
>outside
>of the GNU Radio framework.  E.g., using test-adc or
>mc4020-read-adc? It'll remove one 
>layer of hair in tracking down the problem.

I started by testing the test-adc and mc4020-read-adc programs.
The test-adc always worked great. The mc4020 freezed my computer
at the second run. 

>A few well placed printk's in the driver might shed some light.
>Try mc4020_open, mc4020_release, free_buffer.  Also, I suggest
>#defining VERBOSE_DEBUG to 1 then watching /var/log/kernel/* or
>where ever /etc/syslog.conf directs kernel debugging output

I filled the mc4020-read-adc program with "printf"s and found
that the program freezed at the second run when trying to open
the device. The open function doesn't return.

After comparing the test-adc and MC4020-read-adc programs I
found that adding the following code lines to the
MC4020-read-adc program stopped the computer freezing at the
second run:

  sleep(1);

  //Stop receive
  if((ioctl(fd, GIOCSTOP)) < 0) {
    perror("Failed to stop receive");
  } 
  else 
    fprintf(stderr,"Success: stop receive\n");

  if(close(fd)<0) {
    perror("Failed to close fd");
  } 
  else 
    fprintf(stderr,"Success: close\n");

I also found that the sleep value is a function of the sampling
rate: a lower sampling rate requiers a bigger sleep time to
achive no freeze status at the second run.

Sérgio Rui Silva

P.S.: I will now try to analyse the problem using printk within
the mc4020 driver... 

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