"serial8250: too much work for irq4" logs on Sun Blade X3-2B (X6270 M3)

We are getting multiple "serial8250: too much work for irq4" logs in /var/log/kernel for our Sun Blade X3-2B (X6270 M3) server modules.  From LINUX forum posts, we see that this is due to the serial driver being overloaded (drivers/tty/serial/8250/8250_core.c), however, we do not have excessive serial output. 

At the same time, we could not connect from ILOM GUI (ssh) or CLI
-> SVP (by start /SP/console) -> "xm con".

This may or may not be related to serial8250 error?
So, we are trying to figure out why we are still getting this errors and what we can do to resolve the problem.  Input is appreciated.