Ladies & Gentlemen

I am trying to track down the cause of the failure of a usb connected cell phone to hold a stable connection on the 2.6.26-1-686 kernel.

The machine:
Debian Testing (mostly up-to-date as of 9/17/08)
kde (gnome installed but not used)
network & dhcp server
provides internet service to my small network
firewall

I use kde and kppp to access the cell phone. A Motorola E815. There seams to be a known bug in the firmware in this phone that causes some problems, but that is not this problem.

This does not happen on the 2.6.24-1-686 kernel. I have not tested the .25 kernel I have installed to know if it is affected too.

I think I have the basics established for you. I can give more detail as needed.

The symptoms.

1 launch machine (with or without the phone connected)
2 start kppp and connect to phone
3 open shell, su to root, launch G_SLICE=always-malloc firestarter to prevent firestarter crash.
4 surf web (any machine on my network)
5 at some seemingly random point the internet connection dies
6 kppp tries to reestablish the connection with one of several results
a. the program hangs and must be killed, killing and restarting it does not correct the problem, and when I try to access the phone again it hangs again.
b. reports the phone as busy, disconnecting the phone and rebooting it does not correct the problem.
c. can't find the phone, disconnecting the phone and reconnecting does not correct the problem.
d. occasionally the phone and kppp will say that there is a connection but there is no data transfer, restarting the connection results in one of the above problems.

So, what do you think?

Currently I am running on the 2.6.24 kernel and everything seams to function perfectly. I left the connection going over night and when I came home for lunch it had been connected steady for 13 hours. Sometime shortly after lunch the connection was dropped but kppp reestablished it and when I came home form work it had been connected for 4 more hours.

When I updated to the .26 kernel there were a lot (800+) of packages that needed updating so the problem may be in one of those. I wouldn't think they should work with both, but then again maybe not.

I am not a programmer and I don't know how to narrow down the cause of this before I file a bug report. What is more important is to make sure that it gets filed against the correct package.

So ok; I have for other reasons compiled a custom kernel. I used the config from the 2.6.24 kernel and didn't make any changes to it. So far it seams to be functioning correctly.