'silo overflow' kernel messages

[Lowell Gilbert]

Aleksandr Shapayev <cojet at front.ru> writes:

> FreeBSD 3.5-STABLE worked fine, but after installing 4.8-RELEASE I
> begin receive 'sio1: 1 more silo overflow (total 12)' messages while
> downloading large files.
> 
> 3.5-STABLE produced such messages only after switching to another
> console during file download. All connections were made to the same
> ISP by pppd with same options.
> 
> System configuration: Pentium III (600MHz) with 320Mb RAM, Courier
> V.Everything 56K external modem at /dev/cuaa1.


Something is blocking interrupts for too long.  
Make sure you've got decent FIFOs on your serial port...