[Bitpim-devel] Samsung A620 - small update

[Mike B. <ma...@po...>]

So after days of fighting with timeout errors and blue screens of death
(from trying to work around the timeout errors), I have come to the
conclusion that the proper USB drivers are highly important. :)

I'm currently using a FutureDial cable ("For Samsung model A310, A600").

The first set of samsung drivers I tried to use were the boxwave drivers
found here:
http://www.boxwave.com/products/minisync/samsung/samsung_drivers.zip

These caused me no end of crashes and timeouts.

The new set of samsung drivers that I am using can be found here:
http://www.susteen.com/download/drivers/SamsungCQX.zip

These drivers let me backup the entire filesystem without a single timeout,
which enabled me to remove all of my flawed(?) timeout code.

Just a bit of learning experience, for everyone to possibly benefit from,
here's what I saw and tried before switching drivers:
- First, I was getting a timeout message.  It was consistently reading 198
bytes from a packet that listed the size as 256 bytes.
- To work around this, I changed sendbrewcommand locally to the following:
    def sendbrewcommand(self, request, responseclass, callsetmode=True,
numsendretry=2):
        if callsetmode:
            self.setmode(self.MODEBREW)
        buffer=prototypes.buffer()
        request.writetobuffer(buffer)
        data=buffer.getvalue()
        self.logdata("brew request", data, request)
        data=escape(data+crcs(data))+self.brewterminator
        firsttwo=data[:2]

        isendretry=numsendretry
        while isendretry>=0:
            try:
                self.comm.write(data, log=False) # we logged above
                data=self.comm.readuntil(self.brewterminator,
logsuccess=False)
                break
            except modeignoreerrortypes:
                if isendretry>0:
                    self.log("Resending request packet...")
                    time.sleep(0.3)
                else:
                    self.mode=self.MODENONE
                    self.raisecommsdnaexception("manipulating the
filesystem")
                isendretry-=1

        self.comm.success=True
        origdata=data

        # sometimes there is junk at the begining, eg if the user
	[...]

- This appeared briefly to work.  The first time it retried, it would get
unstuck.  However, it would then give me a bad size exception.  Comparing
the packets sent during a successful read of the file vs an unsuccesful
read, the *only* difference was that the second to last packet from the
phone set the "has more data" flag to false instead of true.  ARGH.
- I then tried, in this situation, to ignore the "has more data" flag and
force it to keep reading anyways.  This led very quickly to a blue screen of
death in my USB drivers.  ARGGGH.
- I then tried to override the getfilecontents function, and wrapped the
whole thing in a try/except block to try to force the entire file read to
restart.  Oddly enough, this also led very quickly to a blue screen of
death, though it's possile I didn't do it correctly.
- Finally, I switched USB drivers, and I was able to go from reading 10-15
files from the filesystem to a full set of 105 or so files.

Time to start poking at the files to see what I can find...

Mike