[Gta04-owner] A word of caution, and developers' non-liability

Neil Jerram neil at ossau.homelinux.net
Sat Sep 15 22:05:36 CEST 2012


Radek Polak <psonek2 at seznam.cz> writes:

> On Saturday, September 15, 2012 03:19:28 PM Neil Jerram wrote:
>
>> Secondly, one of my QtMoko patches caused a regression in v48, which
>> broke SMS sending and also (I think) left the modem in a slightly
>> unusual state after that.
>
> I havent looked yet what happended, but the modem state is really strange - on 
> both Freerunner and GTA04 even reboot does not make it work again.

Well, the problem was that I added a "noResponse" field to
QAtChatCommandPrivate, but didn't always initialise it.  Therefore, in a
sequence of AT commands sent by QtMoko to the modem, the processing of a
random selection of those commands would have not waited for any
response, and then 

- the following AT command could be sent too soon, while the modem was
  still processing the previous one

and/or

- QtMoko could misinterpret the modem's response for that command as
  part of the response to the following AT command.

Given, that, it's easy to see that the modem state could get pretty
strange.  One thing I saw was that my phone was taking much more current
than normal, all the time.

To be sure of resetting that, I shut down, removed the battery, and left
it out for twenty minutes.  Do you agree that that should work?

> On GTA04 it's quite safe thanks to mulltiboot. You can have many partitions on 
> sd card and boot between them.
>
> On GTA02 i'd first try new release from SD card and then flash it to NAND after 
> few days.

Indeed, good points.

>> This is wonderful, pioneering work that we're all doing, and it's great
>> that we have so many participants in that (and, of course, even more
>> would be even better).  But please be aware that participating means
>> understanding and accepting some risk, and taking corresponding care.
>
> Sometimes it's hard to well test the release. There are now 2 devices, each 
> has many features. Testing all features is not for free - e.g. connecting 
> GPRS, calls and SMS costs money and it's a lot of time.

Yes, absolutely.  This was an unspoken assumption in what I wrote, but
it's worth saying explicitly.  It's really hard, and however much
testing we do, we still can't completely eliminate bugs and risks.

> As for QtMoko I hope i can now do less releases better tested. My only big 
> plan is now upgrade to Qt 4.8.2, then just fix bugs and new apps.

(I wonder if we might also need to upgrade to the next Debian stable,
when that happens?)

I hope you don't think that I intended any criticism of you?  Not in the
slightest!  (Or of anyone else here.)

Of course we should all do what testing we can, but I don't think we
should let testing concerns stifle interesting development.

Regards,
        Neil


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