The following is the debug output resulting from starting sigrok-cli like this:

$ ./sigrok-cli -d agilent-dmm:conn=/dev/tty.AgilentU1177A-2C30E6-SPP --samples 1 -O csv -l 4

 

The code in libsigrok/hardware/agilent-dmm/api.c has been changed a bit so that a message is

logged for every serial_* call, giving the return value and errno.

 

sleep(2) has been inserted before various calls, resulting in the output below.

 

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sr: agilent-dmm: sr_serial_dev_inst_new() = 853542336, errno = 60, strerror = Operation timed out

 

sr: agilent-dmm: serial_open() = 0, errno = 60, strerror = Operation timed out

 

sr: agilent-dmm: sleep(2)

sr: agilent-dmm: serial_flush() = 0, errno = 60, strerror = Operation timed out

 

sr: agilent-dmm: serial_write() = 7, errno = 60, strerror = Operation timed out

 

sr: serial: Received 44: 'Agilent Technologies,U1232A,MY53060029,V1.00'.

sr: agilent-dmm: serial_readline() = 0, len = 44, errno = 60, strerror = Operation timed out

 

sr: agilent-dmm: Setting sample limit to 1.

sr: session: Starting.

 

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sr: agilent-dmm: sr_serial_dev_inst_new() = -1998584384, errno = 60, strerror = Operation timed out

 

sr: agilent-dmm: serial_open() = 0, errno = 60, strerror = Operation timed out

 

sr: agilent-dmm: serial_flush() = 0, errno = 60, strerror = Operation timed out

 

sr: agilent-dmm: sleep(2)

sr: agilent-dmm: serial_write() = 7, errno = 60, strerror = Operation timed out

 

sr: serial: Received 44: 'Agilent Technologies,U1232A,MY53060029,V1.00'.

sr: agilent-dmm: serial_readline() = 0, len = 44, errno = 60, strerror = Operation timed out

 

sr: agilent-dmm: Setting sample limit to 1.

sr: session: Starting.

 

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sr: libsigrok loglevel set to 4.

srd: libsigrokdecode loglevel set to 4.

sr: agilent-dmm: sr_serial_dev_inst_new() = -1855978048, errno = 60, strerror = Operation timed out

 

sr: agilent-dmm: serial_open() = 0, errno = 60, strerror = Operation timed out

 

sr: agilent-dmm: serial_flush() = 0, errno = 60, strerror = Operation timed out

 

sr: agilent-dmm: serial_write() = 7, errno = 60, strerror = Operation timed out

 

sr: agilent-dmm: sleep(2)

sr: agilent-dmm: serial_readline() = 0, len = 0, errno = 60, strerror = Operation timed out

 

No devices found.

 

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sr: libsigrok loglevel set to 4.

srd: libsigrokdecode loglevel set to 4.

sr: agilent-dmm: sr_serial_dev_inst_new() = -1050671504, errno = 60, strerror = Operation timed out

 

sr: agilent-dmm: serial_open() = 0, errno = 60, strerror = Operation timed out

 

sr: agilent-dmm: serial_flush() = 0, errno = 60, strerror = Operation timed out

 

sr: agilent-dmm: serial_write() = 7, errno = 60, strerror = Operation timed out

 

sr: agilent-dmm: serial_readline() = 0, len = 0, errno = 60, strerror = Operation timed out

 

No devices found.