I'd like you guys to give a bit of thought to my problem , when you've got time.
I want to use PPP multilinking on the Raspberry Pi but I cannot seem to get a stable setup so I can move on.
On each setup , the ethernet gives out write errors or stops (I know it's usually a power supply problem but read along).
I have an 7 port USB hub powered with 2.5A supply , and I connect everything through that ( so only one USB from the Pi is used to connect to the hub).
Powering the Raspberry from the hub and with one 3g modem ( voltage on tp1-tp2 is about 4.85V) works very well giving no kernel messages , when I connect the second , the ethernet and whole system is very slow ( pings take 5-8 secs) (tp1-tp2 4.7V ) so unstable because of the voltage.
Then I tried to power the Raspberry separately with a 5V.700mA Samsung Galaxy adapter , with the same effects . (it seems to me that the setup is more stable powering the Pi from the hub)(tp1-tp2 gets 5.01V constant)
Then I was thinking that maybe the hub is actually draining power from the raspberry (there was no measured voltage drop, but still) I covered the power pins on the usb that comes from the hub into the raspberry (the board still powered from the samsung adapter) so I would be sure that there is no electrical connection (like on bus powered hubs) and only the data pins.Still the setup is very unstable.
Then I noticed that blacklisting the option driver not to load at boot , produced a stable system (until i modprobe option) of course. (it's stable even powering everything from the usb hub).
Can any of you actually get two modems usable on the raspberry Pi (to have 2-6 ttyusb devices in /dev) and maybe dial each one ? If yes , please oo please share what setup you managed to do that with .
I used Debian squeeze,wheezy(official images) and now I will try arch linux (but initial results are the same...modems get recognized and ethernet goes crazy , tp1-tp2 has 4.9V )
Thank you for reading this long post...
I would appreciate any help,
BR