noapic doesn't quite work as advertised

noapic doesn't quite work as advertised

[Andy Arvai]

Hi,

I've got a tyan s2520 motherboard (dual PIII + i840) which is having a
problem with APIC errors. I tried running with noapic, but there were
still errors, although fewer. Does anyone have any idea what is going
on? I'm running 2.4.4 and software raid5, which generates a lot of
interrupts.

Here are some of the APIC errors (with noapic):

May 21 12:38:31 rad kernel: APIC error on CPU0: 02(01)
May 21 12:42:31 rad kernel: APIC error on CPU0: 01(01)
May 21 12:42:31 rad kernel: APIC error on CPU1: 02(02)
May 21 12:43:13 rad kernel: APIC error on CPU0: 01(02)
May 21 12:43:13 rad kernel: APIC error on CPU1: 02(01)
May 21 13:48:19 rad kernel: SCSI disk error : host 3 channel 0 id 0 lun 0 return code = 8000002
May 21 13:48:19 rad kernel: [valid=0] Info fld=0x0, Current sd08:d2: sense key Aborted Command
May 21 13:48:19 rad kernel: Additional sense indicates Scsi parity error
May 21 13:48:19 rad kernel:  I/O error: dev 08:d2, sector 56590336
May 21 13:48:19 rad kernel: interrupting MD-thread pid 1223
May 21 13:48:19 rad kernel: raid5: parity resync was not fully finished, restarting next time.

Here is /proc/interrupts to prove I'm really running with noapic:

           CPU0       CPU1       
  0:   17760464          0          XT-PIC  timer
  1:      29525          0          XT-PIC  keyboard
  2:          0          0          XT-PIC  cascade
  3:   27416165          0          XT-PIC  eth1
 11:  188276091          0          XT-PIC  aic7xxx, aic7xxx, aic7xxx, aic7xxx
 12:     413496          0          XT-PIC  PS/2 Mouse
 14:    1137884          0          XT-PIC  ide0
 15:    1740847          0          XT-PIC  ide1
NMI:          0          0 
LOC:   17760053   17759969 
ERR:         31

Right now I'm running with noapic and nosmp and so far this seems to
be working. I really would like to be able to use the second
cpu so any suggestion would be greatly appreciated.

Andy
arvai@scripps.edu

Re: noapic doesn't quite work as advertised

[Studierende der Universitaet des Saarlandes]

> 've got a tyan s2520 motherboard (dual PIII + i840) which is having a 
> problem with APIC errors. I tried running with noapic, but there were 
> still errors, although fewer. Does anyone have any idea what is going 
> on? I'm running 2.4.4 and software raid5, which generates a lot of 
> interrupts. 

noapic only prevents that hardware interrupts are rerouted through the
io apic.

The inter processor interrupts still use the apic bus, and it's
impossible to use SMP without IPIs.

> Right now I'm running with noapic and nosmp and so far this seems to 
> be working. I really would like to be able to use the second 
> cpu so any suggestion would be greatly appreciated. 

It could be a hardware problem, or the board uses an unusal io apic
that's not properly handled.
If you boot without noapic, are there any unusual message in the boot
log?

Perhaps
	MP-BIOS bug
	unknown io apic
etc.