[ECOS] Flag query

Bell, Andrew [Allen & Heath UK] Andrew.Bell@allen-heath.com
Fri Oct 27 14:38:00 GMT 2006

Hello All

I'm still trying to diagnose a netstack stall, and have traced the
packet delivery through my fec driver, into the generic Ethernet driver
and into if_ethersubr.c which demuxes the different protocols and then
calls software interrupts using schednetisr. In eCos this function seams
to be implemented using flags, the network thread sleeps on
cyg_flag_wait, and when schednetisr or's in a bit signaling a particular
protocol has arrived and is ready for a push into the protocol stack
cyg_netint in support.c is suppose to wake and call the appropriate
netisr handler. Fine. 

My trace shows the call to schednetisr, and inside flags.cxx I can see
setbits is called, but cyg_netint (network thread) fails to wake. My
question .... Is there a good way of debugging the scheduling loop, from
what I can see the bottom of setbits in flags.cxx should call
Cyg_Scheduler::unlock, shouldn't this cause a reschedule ? My network
thread priority in higher than any user thread (lower numerically), im
kind of hoping for a context switch. Eventually my connection gets
dropped as the starvation of my tcp/ip stack means no acks are being

Any help as always would be greatly appreciated.

Many Thanks


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