2.6.18-rc5-mm1 unusual IRQ number for VIA device

2.6.18-rc5-mm1 unusual IRQ number for VIA device

[Jay Cliburn]

Running 2.6.18-rc5.mm1 on an Asus M2V mainboard with dual-core Athlon 
cpu, the onboard audio device gets assigned and IRQ of 8410.  Under 
2.6.18-rc4-mm3, the same device gets assigned IRQ 17.  Is this a way to 
get around this?

/proc/interrupts:
            CPU0       CPU1
   0:     525177          0   IO-APIC-edge     timer
   1:       3016          0   IO-APIC-edge     i8042
   6:          5          0   IO-APIC-edge     floppy
   7:          0          0   IO-APIC-edge     parport0
   8:          0          0   IO-APIC-edge     rtc
   9:          0          0   IO-APIC-fasteoi  acpi
  12:          4          0   IO-APIC-edge     i8042
  14:      18433          0   IO-APIC-edge     ide0
  20:      16017          0   IO-APIC-fasteoi  uhci_hcd:usb1
  21:      66080          0   IO-APIC-fasteoi  uhci_hcd:usb3, 
ehci_hcd:usb5, libata
  22:          0          0   IO-APIC-fasteoi  uhci_hcd:usb2
  23:          0          0   IO-APIC-fasteoi  uhci_hcd:usb4
  36:       4600          0   IO-APIC-fasteoi  eth0
8410:        193          0   PCI-MSI-<NULL>  HDA Intel
NMI:        180         91
LOC:     525078     525029
ERR:          0

And here's the lspci output for the audio device:
08:01.0 Audio device: VIA Technologies, Inc. VIA High Definition Audio 
Controller (rev 10)
         Subsystem: ASUSTeK Computer Inc. Unknown device 81e7
         Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- 
ParErr- Stepping- SERR- FastB2B-
         Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- 
<TAbort- <MAbort- >SERR- <PERR-
         Latency: 0, Cache Line Size: 64 bytes
         Interrupt: pin A routed to IRQ 8410
         Region 0: Memory at fbffc000 (64-bit, non-prefetchable) [size=16K]
         Capabilities: [50] Power Management version 2
                 Flags: PMEClk- DSI- D1- D2- AuxCurrent=55mA 
PME(D0+,D1-,D2-,D3hot+,D3cold+)
                 Status: D0 PME-Enable- DSel=0 DScale=0 PME-
         Capabilities: [60] Message Signalled Interrupts: 64bit+ 
Queue=0/0 Enable+
                 Address: 00000000fee00000  Data: 406a
         Capabilities: [70] Express Unknown type IRQ 0
                 Device: Supported: MaxPayload 128 bytes, PhantFunc 0, 
ExtTag-
                 Device: Latency L0s <64ns, L1 <1us
                 Device: Errors: Correctable- Non-Fatal- Fatal- Unsupported-
                 Device: RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop-
                 Device: MaxPayload 128 bytes, MaxReadReq 128 bytes
                 Link: Supported Speed unknown, Width x0, ASPM unknown, 
Port 0
                 Link: Latency L0s <64ns, L1 <1us
                 Link: ASPM Disabled CommClk- ExtSynch-
                 Link: Speed unknown, Width x0
         Capabilities: [100] Virtual Channel
00: 06 11 88 32 06 04 10 00 10 00 03 04 10 00 00 00
10: 04 c0 ff fb 00 00 00 00 00 00 00 00 00 00 00 00
20: 00 00 00 00 00 00 00 00 00 00 00 00 43 10 e7 81
30: 00 00 00 00 50 00 00 00 00 00 00 00 01 01 00 00
40: 00 30 00 00 00 00 00 00 00 00 00 00 00 00 00 00
50: 01 60 42 c8 00 00 00 00 00 00 00 00 00 00 00 00
60: 05 70 81 00 00 00 e0 fe 00 00 00 00 6a 40 00 00
70: 10 00 91 00 00 00 00 00 00 00 30 00 00 00 00 00
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Re: 2.6.18-rc5-mm1 unusual IRQ number for VIA device

[Jay Cliburn]

Jay Cliburn wrote:
> Running 2.6.18-rc5.mm1 on an Asus M2V mainboard with dual-core Athlon 
> cpu, the onboard audio device gets assigned and IRQ of 8410.  Under 
> 2.6.18-rc4-mm3, the same device gets assigned IRQ 17.  Is this a way to 
> get around this?

What I meant to ask is:  Is there a way to get around this?

Thanks,
Jay

Re: 2.6.18-rc5-mm1 unusual IRQ number for VIA device

[Robert Hancock]

Jay Cliburn wrote:
> Jay Cliburn wrote:
>> Running 2.6.18-rc5.mm1 on an Asus M2V mainboard with dual-core Athlon 
>> cpu, the onboard audio device gets assigned and IRQ of 8410.  Under 
>> 2.6.18-rc4-mm3, the same device gets assigned IRQ 17.  Is this a way 
>> to get around this?
> 
> What I meant to ask is:  Is there a way to get around this?
> 
> Thanks,
> Jay

What do you think needs to be "gotten around"? It is using MSI 
interrupts, I think that the IRQ numbers will be different.

-- 
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/

Re: 2.6.18-rc5-mm1 unusual IRQ number for VIA device

[Jay Cliburn]

Robert Hancock wrote:
> Jay Cliburn wrote:
>> Jay Cliburn wrote:
>>> Running 2.6.18-rc5.mm1 on an Asus M2V mainboard with dual-core Athlon 
>>> cpu, the onboard audio device gets assigned and IRQ of 8410.  Under 
>>> 2.6.18-rc4-mm3, the same device gets assigned IRQ 17.  Is this a way 
>>> to get around this?
>>
>> What I meant to ask is:  Is there a way to get around this?
>>
>> Thanks,
>> Jay
> 
> What do you think needs to be "gotten around"? It is using MSI 
> interrupts, I think that the IRQ numbers will be different.
> 

I'll have to go research what MSI interrupts are.  Thanks for the pointer.

Unfortunately, Fedora Core's irqbalance segfaults when it encounters the 
IRQ of 8410.  I assumed this behavior indicated that an IRQ number 
shouldn't be that large.

Thanks again.

Re: 2.6.18-rc5-mm1 unusual IRQ number for VIA device

[Jay Cliburn]

Jay Cliburn wrote:
> Robert Hancock wrote:
>> Jay Cliburn wrote:
>>> Jay Cliburn wrote:
>>>> Running 2.6.18-rc5.mm1 on an Asus M2V mainboard with dual-core 
>>>> Athlon cpu, the onboard audio device gets assigned and IRQ of 8410.  
>>>> Under 2.6.18-rc4-mm3, the same device gets assigned IRQ 17.  Is this 
>>>> a way to get around this?
>>>
>>> What I meant to ask is:  Is there a way to get around this?
>>>
>>> Thanks,
>>> Jay
>>
>> What do you think needs to be "gotten around"? It is using MSI 
>> interrupts, I think that the IRQ numbers will be different.
>>
> I'll have to go research what MSI interrupts are.  Thanks for the pointer.

Nothing I've read about MSI so far indicates that an IRQ number greater 
than 255 is permissible, yet this device gets assigned an IRQ number of 
8,410 when MSI is enabled.  Booting 2.6.18-rc5-mm1 with pci=nomsi causes 
the device to be assigned IRQ 17 instead of 8410.

The problem with the large IRQ number is made manifest in Fedora's 
irqbalance program, which is run as an init script.  An array is built 
in that program that's indexed by IRQ number, with a max of 255.  When 
the program attempts to index element 8410, it segfaults.

Are IRQ numbers greater than 255 allowed with MSI?

Re: 2.6.18-rc5-mm1 unusual IRQ number for VIA device

[Andrew Morton]

On Mon, 04 Sep 2006 10:26:21 -0500
Jay Cliburn <jacliburn@bellsouth.net> wrote:

> Jay Cliburn wrote:
> > Running 2.6.18-rc5.mm1 on an Asus M2V mainboard with dual-core Athlon 
> > cpu, the onboard audio device gets assigned and IRQ of 8410.  Under 
> > 2.6.18-rc4-mm3, the same device gets assigned IRQ 17.  Is this a way to 
> > get around this?
> 
> What I meant to ask is:  Is there a way to get around this?
> 

MSI is rather busted and has been redone.  Disabling CONFIG_MSI
may well help.

Re: 2.6.18-rc5-mm1 unusual IRQ number for VIA device

[Robert Hancock]

Jay Cliburn wrote:
> Nothing I've read about MSI so far indicates that an IRQ number greater 
> than 255 is permissible, yet this device gets assigned an IRQ number of 
> 8,410 when MSI is enabled.  Booting 2.6.18-rc5-mm1 with pci=nomsi causes 
> the device to be assigned IRQ 17 instead of 8410.
> 
> The problem with the large IRQ number is made manifest in Fedora's 
> irqbalance program, which is run as an init script.  An array is built 
> in that program that's indexed by IRQ number, with a max of 255.  When 
> the program attempts to index element 8410, it segfaults.
> 
> Are IRQ numbers greater than 255 allowed with MSI?

I assume you're on x86-64 with CONFIG_NR_CPUS set to 255. In that case 
the max IRQ number is 256 + (32 * NR_CPUS) or 8416. The MSI interrupts 
will get assigned from highest IRQ to lowest, so you should expect to 
see such high numbers..

It appears that irqbalance's assumption that IRQ cannot exceed 255 is 
not valid on x86-64 (on i386 it is since NR_IRQS is 224).

-- 
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/