kern/118093: firewire bus reset hogs CPU, causing data to be lost

[Dieter]

Here are the results of two more experiments:

I tried to verify what spl the firewire code is at when calling
printf(9) by adding the following block into fwohci.c just
before one of the printfs.

{
#include <sys/types.h>
#include <sys/systm.h>
  intrmask_t debug_spl;  /* __uint32_t */
  intrmask_t debug_spl_high;
  intrmask_t debug_spl_tty;
  intrmask_t debug_spl_fw;
  intrmask_t debug_spl_0;
  intrmask_t debug_spl_net;

  debug_spl = splhigh();
  debug_spl_high = spltty();
  debug_spl_tty = splfw();
  debug_spl_fw = splnet();
  debug_spl_net = splhigh();
  spl0();  /* void */
  debug_spl_0 = splhigh();
  splx(debug_spl);

  printf("fwohci_intr_core(): spl = 0x%x\n splhigh=0x%x spltty=0x%x splfw=0x%x splnet=0x%x spl0=0x%x\n",
         debug_spl, debug_spl_high, debug_spl_tty, debug_spl_fw, debug_spl_net, debug_spl_0);
}

But my results appear bogus:

fwohci_intr_core(): spl = 0x0
 splhigh=0x0 spltty=0x0 splfw=0x0 splnet=0x0 spl0=0x0

I have examined my code and the spl(9) man page several times
but I can't find what is wrong.  Any clues?

--------------------------------------------------------

To isolate the effects of printf(9) from the firewire bus reset,
I picked a trivial system call (chown(2)) and added some printf(9)
calls.

Calling chown several times and monitoring with systat -vmstat gives:
  1098 interrupts on the console IRQ
  93.1%Sys   6.7%Intr  0.2%User  0.0%Nice  0.0%Idle

This did NOT interfere with Ethernet.

So printf(9) interferes with Ethernet when called from the
firewire driver, but not when called from a vanilla system call.

--------------------------------------------------------

sio0: <16550A-compatible COM port> port 0x3f8-0x3ff irq 4 flags 0x10 on acpi0
sio0: type 16550A, console
sio0: [FILTER]

What does [FILTER] mean?  I don't see an explanation on the sio man page.