First time subsurace usage surprises

[Jef Driesen]

On 2012-07-31 01:28, Lutz Vieweg wrote:
> While reading data from my D9 I got some "failed to receive the
> answer" messages. From looking at the mailing list archive, I
> understand this phenomenon is not really understood as of today. I'll
> do my best trying to figure out what it's about. My knowledge of
> serial communication lines, though, is from the time when "kermit" 
> was
> a new protocol, so I wonder whether this knowledge is still 
> applicable
> in the USB-3.0 era.
> (And actually, USB drivers of all kinds are amongst the least stable
> drivers I have ever experienced under any OS... *shudder*... ;-)

If the download is successful, you can ignore these messages. Sometimes 
the dive computer doesn't respond immediately, a corrupted packet is 
received, etc. In that case the libdivecomputer library will simply 
retry the failed packet. If it's just an occasional failure, then the 
retrying will work fine and there is nothing to worry about. If you get 
many failed packets, then libdivecomputer will eventually give up and 
return an error.

Jef