Subject: Re: com rumblings...
To: Garrett D'Amore <>
From: Garrett D'Amore <>
List: tech-kern
Date: 06/15/2006 13:22:50
David Laight wrote:
> On Thu, Jun 15, 2006 at 12:54:53PM -0700, Garrett D'Amore wrote:
>> I need to verify what we are seeing though -- is it a hardware FIFO
>> overrun, or the ring buffer filling up?  com(4) shows hardware fifo
>> overflows as "silo overflows" and ring buffer fills as "ibuf floods".
> They were silo overflows - which is why I suspect other ISR an/or splhi().
> And why it would be tricky to debug them...
> (The 'easy' way is to connect the IRQ line from the UART to a logic
> analiser timing port, set it to trigger on the signal being active
> for > some_time, connect the trigger-out of the analiser to the systems
> NMI line, and use the NMI to enter ddb, then look at the traceback.)
> 	David

Heh, "easy".  I don't have a logic analyzer handy.  This also sounds
almost certainly like an i386-specific problem. :-)

Garrett D'Amore, Principal Software Engineer
Tadpole Computer / Computing Technologies Division,
General Dynamics C4 Systems
Phone: 951 325-2134  Fax: 951 325-2191