Dive data import error with Hollis DG03

[Rick Walsh]

On 25 March 2014 01:00, Rick Walsh <rickmwalsh at gmail.com> wrote:
> On 25 March 2014 00:29, Jef Driesen <jef at libdivecomputer.org> wrote:
>> At the moment my preference is towards this adaptive delay solution,
>> assuming it works of course. Could you give the attached patch a try?
>> Preferable on multiple systems (Linux, Windows) and both with and without
>> the 16ms low latency timer. The patch starts with a delay of 0ms, and
>> increases it with 4ms on every failure. That's just a proof of concept of
>> course. We can easily change the logic depending on what works best.
>
> The patch works for me on Linux. I rebuilt libdivecomputer, then
> subsurface. Building on/for Windows is beyond me.
>
> latency_timer is left at 1 (not using setserial or udev rules).
>
> There is one error in the log file from subsurface (Unexpected answer
> start byte(s)), then it sleeps. I'm guessing that's exactly what you
> want it to do.

As the delay was only increased once, to 4ms, I tried reducing the
delay increment to 1ms by editing oceanic_atom2.c (after applying your
patch)

--- oceanic_atom2.c~    2014-03-25 07:59:35.608749961 +1100
+++ oceanic_atom2.c    2014-03-25 07:33:23.549403357 +1100
@@ -369,7 +369,7 @@
         if (nretries++ >= MAXRETRIES)
             return rc;

-        device->delay += 4;
+        device->delay += 1;

         // Delay the next attempt.
         serial_sleep (device->port, 100);


For me this worked just as well as the delay increment of 4ms.
Downloading from my DC in subsurface, I get one error line (line 34)
in the log, and every subsequent Write is preceded by Sleep: value=1.
The sleep value never increases beyond 1ms.

(line 34)
ERROR: Failed to receive the answer. [in oceanic_atom2.c:337
(oceanic_atom2_send)]
INFO: Sleep: value=100
INFO: Flush: queue=1, input=0, output=0
INFO: Sleep: value=1
...
INFO: Write: size=4, data=B10F0900
INFO: Read: size=1, data=5A
INFO: Read: size=17, data=40060003048C8C8C99070501020200029D
INFO: Sleep: value=1
INFO: Write: size=4, data=6A05A500
INFO: Read: size=1, data=A5
(EOF)



I also tried downloading from my DC with
/sys/bus/usb-serial/devices/ttyUSB0/latency_timer set to 16.
Essentially, it does the same as above, but the error line doesn't
occur until line 6649, so it gets nearly halfway through downloading
before it needs to introduce the 1ms delay.

This looks promising - the patch works as it should, and there's no
need to get root privilege or play with /sys/ files. Note, I haven't
tested on other hardware or OSs.