Changing 945G GPU IRQ assignment

[Justin Piszcz]

Do you boot with noapic?

On Wed, 30 Sep 2009, Justin Piszcz wrote:

> Hi Hugo,
>
> I use a DG965 board currently with built-in video and a 3ware card in the x16 
> slot:
>
> $ cat /proc/interrupts
>           CPU0       CPU1       CPU2       CPU3
>  0:       3241          0          0          0   IO-APIC-edge      timer
>  1:          2          0          0          0   IO-APIC-edge      i8042
>  8:          1          0          0          0   IO-APIC-edge      rtc0
>  9:          0          0          0          0   IO-APIC-fasteoi   acpi
> 12:          3          0          0          0   IO-APIC-edge      i8042
> 16:    4383796   12792529    5711773    5079069   IO-APIC-fasteoi   3w-9xxx, 
> uhci_hcd:usb3
> 18:      57977      14740          0          0   IO-APIC-fasteoi 
> ehci_hcd:usb1, uhci_hcd:usb7
> 19:      35308      35028          0          0   IO-APIC-fasteoi 
> uhci_hcd:usb6
> 21:      57951   77630159    3692228   99277364   IO-APIC-fasteoi 
> uhci_hcd:usb4, eth1
> 22:     552076    6937190   17079516   15588018   IO-APIC-fasteoi   HDA 
> Intel, eth2
> 23:    3448429   13678957          0          0   IO-APIC-fasteoi 
> ehci_hcd:usb2, uhci_hcd:usb5
> 30:     455701     209453          0          0   PCI-MSI-edge 
> i915 at pci:0000:00:02.0
> 31:     861003    3495076       9393    3194492   PCI-MSI-edge      ahci
> 32:    2621566   20858202    5466083   85380656   PCI-MSI-edge      eth0
>
> If you play around with the kernel options, I believe there is an option to
> move things around so it goes onto its own IRQ (the graphics card).  I will
> see if I can remember what it was, I had the same issue, i915 was on the same
> IRQ as the 3ware card I believe.  I do not recall off-hand which option it 
> was.
> Will take a look and report back if I find anything.
>
> Justin.
>
>
> On Wed, 30 Sep 2009, Jacques, Hugo wrote:
>
>> Hi,
>> 
>> I have an Intel 945G-based system on which I installed a custom board 
>> (qhal_host below) into the PCIe x16 slot.
>> 
>> I am running Linux 2.6.29.6, Xorg 1.6.0 and xf86-video-intel 2.7.0.
>> 
>> Is there a way to have the Integrated Graphics Controller 
>> (i915 at pci:0000:00:02.0 below) being assigned to an IRQ different than 16?
>> 
>> I am asking this because I want to debug an interrupt issue. At some point 
>> I get ~100000 interrupts a second on IRQ16 despite neither the qhal_host or 
>> the Intel GPU devices report the interrupt is theirs (through respective 
>> IIR registers).
>> 
>> Anybody heard of 945G issues when both the GPU and a card in the PCIe x16 
>> slot are generating interrupts as the same time?
>> 
>> Thanks in advance.
>> 
>> cat /proc/interrupts
>>           CPU0       CPU1
>>  0:         71          0   IO-APIC-edge      timer
>>  1:          2          0   IO-APIC-edge      i8042
>>  2:          0          0    XT-PIC-XT        cascade
>>  4:         10          0   IO-APIC-edge
>>  9:          0          0    XT-PIC-XT        acpi
>> 14:       7882          0   IO-APIC-edge      ide0
>> 16:       8586          0   IO-APIC-fasteoi 
>> qhal_host,i915 at pci:0000:00:02.0
>> 28:       5872          0   PCI-MSI-edge      eth0
>> 30:          0          0   PCI-MSI-edge      ahci
>> NMI:          0          0   Non-maskable interrupts
>> LOC:    2170197    2053944   Local timer interrupts
>> RES:        754        957   Rescheduling interrupts
>> CAL:         35         22   Function call interrupts
>> TLB:        409        421   TLB shootdowns
>> TRM:          0          0   Thermal event interrupts
>> SPU:          0          0   Spurious interrupts
>> ERR:          0
>> MIS:          0
>> 
>> 
>> 
>> 
>>  
>> Hugo Jacques, ing.
>> Video Tech Leader
>> Video Intelligence Solutions
>> Verint Systems Inc.
>> 
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