I2C exception handling.

could it be that there is NONE?
could it be that the device (Q2686H in this case) silently restarts, leaving the I2C bus in an unusable state?

-edit-
to clearify the problem a bit
some traces from Target monitor

Trace	SYS	2	[knocker_addKnockNow] Knocking on 0
Trace	SYS	2	[sc_groupSend] sending action : 0
Trace	SYS	3	gpio: input 0 triggered
Trace		1	Unable to find the string of the remote trace in the file (ID = 34831)
Trace		1	Unable to find the string of the remote trace in the file (ID = 33768)
Trace	SYS	2	gpioRead 0x180C4404 Failed
Trace		1	Unable to find the string of the remote trace in the file (ID = 34831)
Trace		1	Unable to find the string of the remote trace in the file (ID = 33768)
Trace	SYS	2	gpioWrite 0x180C4404 Failed

and then it resets leaving the I2C bus in an unrecoverable state