[chirp_devel] [PATCH][BTECH] Bug fix about radios resetting on the download, fixes #3015

[Pavel Milanes (CO7WT)]

El 08/04/16 a las 17:31, Dan Smith via chirp_devel escribió:
> So we could go with a timeout of 5 minutes then right? I'm being
> hyperbolic, but what I mean is, you only ever need a short timeout if
> you're reading more than is available...

The general (default) timeout is set to 0.7 secs, because we have a 
bunch of radios to deal with, and this radios put some particular pauses 
(each models has it's own pauses as high as 0.5 secs in some cases) 
between the request and the answer of a block.

Aka: we have really a ~0.2 sec timeout for the radios that has the long 
pause, and the others just continue when it has the right amount of data 
(69 bytes), this works ok with all radios with no timeouts or other 
failures.

The problem is in the radios with the read in the high mem zone (second 
id) it just read 16 bytes instead of the normal 64 bytes, so the timeout 
must be short here because in this particular moment some times the 
radios put a misplaced \x05 (we call it 'wrong ACK', it can be a bug or 
a feature, who knows) that make the requested block of 16 bytes short by 
one.

normally  ACK + 4 bytes of headers + 16 bytes payload (21 bytes)
with the wrong ack it's like this: WRONG-ACK + 4 bytes of headers + 15 
bytes payload (20 bytes)

When the wrong ack appears in the stream the block is just 20 bytes 
instead of the normal 21; so the driver get waiting to the normal 0.7 
sec of timeouts and the radio resets getting itself out of the clone mode.

This is the root of the problem, my way of solving that is to lower the 
timeout to allow to capture at least the 20 incomplete bytes and timeout 
ASAP to keep in sync with the radio, because we only care about 12 bytes 
in there and don't care about if the full 16 or 15 byte were received, 
I'm happy with the first 12 in the payload because in there is out check 
string.

In fact the rest of the 4 or 3 bytes are different in each radio model, 
some times full \x00, some times \xFF and even \x20

Doing it like this allows me to keep going fast into the normal read and 
it works.

Cheers.