irq conflict of pcm0 & vge0 devices on Abit AV8 cause high CPU load

[Alexander Konovalenko]

Hi!

The gigabit NIC (vge0) on Abit AV8 did not work well when I got this 
matherboard at work, so I disabled this interface in the BIOS and use PCI NIC 
(fxp0) instead. The problem was that after 3-4 days after boot vge0 suddenly 
reports "no carrier" and the only way to bring it back was to reboot again.

My recent AMD64 X2 upgrade followed with BIOS upgrade (to v2.4) and apparently 
vge0 was enabled again. Then after couple of days I noticed high CPU (both 
cores) load:

---------------------------------------------
systat:
                    /0   /1   /2   /3   /4   /5   /6   /7   /8   /9   /10
     Load Average   |||||||||||||

                    /0   /10  /20  /30  /40  /50  /60  /70  /80  /90  /100
root     irq22: pcm XXXXXXXXXXXXXXXXXXXXXXXXX

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

vmstat -i:
interrupt                          total       rate
irq1: atkbd0                       27286          0
irq0: clk                      204987922       1000
irq6: fdc0                             9          0
irq8: rtc                       26234430        127
irq12: psm0                      1967122          9
irq14: ata0                           46          0
irq18: fxp0                      6270446         30
irq20: atapci0                   1760077          8
irq22: pcm0 vge0               918487906       4481
irq23: fwohci0                         1          0
Total                         1159735245       5658

---------------------------------------------
top -S:

PID USERNAME PRI NICE   SIZE    RES STATE  C   TIME   WCPU    CPU COMMAND
34 root     -80 -199     0K    16K CPU1   1 214:29 98.05% 98.05% irq22: pcm0


I am not sure if there is a conflict between sound device pcm0 and vge0 but 
audio output generates low frequency noise, I tried to unload sound module 
but it did not work reporting "device busy". Probably I can solve this 
problem by rebooting and disabling vge0 in BIOS but I have two simulations 
running for couple of days and have no wish to interrupt them.

 My question is, how can I stop this irq22 process safely? Is it OK to just 
kill it?

PS: I have 5.4-STABLE

/Alexander Konovalenko

+46-8-5537-8142 (office)
+46-7-3752-2116
http://daemon.nanophys.kth.se/~kono

Royal Institute of Technology (KTH)
Nanostructure Physics Department, Albanova
Roslagstullsbacken 21
10691 Stockholm
Sweden