Add troubleshooting instructions to user manual

Let's cover at least the most common problem (modem manager interfering)
and also have instructions of how to dump debug log from the transfer.

Signed-off-by: Miika Turkia <miika.turkia@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 40 insertions, 1 deletions

diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt
index 63647f8d3..2ef8314ee 100644
--- a/Documentation/user-manual.txt
+++ b/Documentation/user-manual.txt
@@ -444,7 +444,11 @@ work for you :-).
 For downloading dives in subsurface you have then to specify '/dev/rfcomm0'
 as device name to use.
 
-Troubleshooting:
+[[S_TroubleShooting]]
+Troubleshooting
+~~~~~~~~~~~~~~~
+**Bluetooth**
+
 Using Bluetooth for downloading from dive computers on Linux seems to be tricky
 some times. If you have issues please have a look to the following notes. Using
 a Shearwater Predator you may be able to pair but then encounter issues when
@@ -462,6 +466,41 @@ Please report issues and nonworking environments at
 http://trac.hohndel.org[our bugtracker] or send an email to
 mailto:subsurface@hohndel.org[our mailing list].
 
+**USB**
+
+It is somewhat common that Modem Manager (or some other application)
+interferes with dive computers when using a USB serial connection. You
+might see errors similar to the following:
+
+	ERROR: Device or resource busy (16) [in serial_posix.c:107 (serial_open)]
+
+This often means that another application has opened the serial port
+in exclusive mode and should be disabled prior to connecting the dive
+computer.
+
+	sudo /etc/init.d/modemmanager stop
+
+**Getting debug logs**
+
+Getting debug logs or full memory dump of the dive computer might be
+needed to solve the issue. This can be don with libdivecomputer's
+universal application (you can compile it yourself or download from
+http://www.libdivecomputer.org/builds/[libdivecomputer's
+web page] - select the operating system of your choice and download the
+*universal* binary from there). Debug log can be obtained with the
+following command (change the DC name and model appropriately):
+
+	./universal -l output.log -d output.xml -n "Oceanic Geo 2.0" -v /dev/ttyUSB0
+
+This will produce an *output.log* that you should send to mailto:subsurface@hohndel.org[our mailing list].
+
+A full memory dump can be obtained similarly:
+
+	./universal -l output.log -m output.bin -n "Oceanic Geo 2.0" -v /dev/ttyUSB0
+
+NOTE: you can get a short help of the universal application along with a
+list of supported devices by running it without parameters.
+
 [[S_ViewingLogs]]
 Viewing and Completing Your Logs
 --------------------------------