2.6.{30,31} x86_64 ahci problem - irq 23: nobody cared

[Alexander Huemer <alexander.huemer@sbg.ac.at>]

the problem appears under heavy system load and slows down the system to
unusable speed.
kernels before .30 were not affected.
irqpoll does not change behavior.

error message from .31:

    [157152.418524] irq 23: nobody cared (try booting with the "irqpoll"
    option)
    [157152.418530] Pid: 1359, comm: cc1plus Tainted: G        W 
    2.6.31-gentoo-blackbit #2
    [157152.418532] Call Trace:
    [157152.418534]  <IRQ>  [<ffffffff81066e3f>] ?
    __report_bad_irq+0x30/0x7d
    [157152.418544]  [<ffffffff81066f93>] ? note_interrupt+0x107/0x170
    [157152.418547]  [<ffffffff81067580>] ? handle_fasteoi_irq+0x8a/0xaa
    [157152.418551]  [<ffffffff8100d1cf>] ? handle_irq+0x17/0x1d
    [157152.418554]  [<ffffffff8100c84b>] ? do_IRQ+0x54/0xb2
    [157152.418558]  [<ffffffff8100b6d3>] ? ret_from_intr+0x0/0xa
    [157152.418559]  <EOI>
    [157152.418560] handlers:
    [157152.418562] [<ffffffff813d2a6f>] (ahci_interrupt+0x0/0x426)
    [157152.418566] Disabling IRQ #23


bios of the machine is up to date,
i tried all related bios settings, no change.

kernel config for .31     http://xx.vu/~ahuemer/config_ahuemer_20090923.gz
lspci -vxxx               http://xx.vu/~ahuemer/lspci_ahuemer_20090923
lsusb -v                  http://xx.vu/~ahuemer/lsusb_ahuemer_20090923
/proc/interrupts         
http://xx.vu/~ahuemer/proc_interrupts_ahuemer_20090923
thread in gentoo forums  
http://forums.gentoo.org/viewtopic-t-780725-start-0.html

please tell me what additional info is needed.
please CC me on replies, i am not subscribed.

-alex