ppp over serial problems in lk 4.0.x

Since lk 4.0.0 came out running ppp connected to a serial port (GPRS) has failed on my hardware (at91sam9g25 based ARM system). It works in lk 3.19-rc4 which is the last kernel I tried prior to lk 4.0.0 . The fix to ppp_generic.c in lk 4.0.2 did not help.

With older kernels I see:

...
chat[1760]: ATD*99***1#^M^M
chat[1760]: CONNECT
chat[1760]: -- got it
chat[1760]: send (^M)
pppd[1758]: Serial connection established.
pppd[1758]: Using interface ppp0
...

and about 5 ppp related modules loaded including ppp_async.

With lk 4.0.x the "Serial connection established" line never appears and only the ppp_generic module is loaded.

I get the same results (i.e. depends on the kernel version) with both an up to date Debian 7 (wheezy) and a freshly minted Debian 8 (jessie) system.

Doug Gilbert