threadirqs && irq nobody cared

From: Tim Blechmann
Date: Sun Oct 02 2011 - 19:09:45 EST

hi all,

i've experienced problems with recent kernels that irqs are disabled. there
was a similar report some time ago on lkml, suggesting that it might be an
issue with threaded irqs [1].

my issue looked similar:
[ 14.726028] irq 16: nobody cared (try booting with the "irqpoll" option)
[ 14.726032] Pid: 46, comm: irq/16-uhci_hcd Tainted: P 3.0.1 #12
[ 14.726035] Call Trace:
[ 14.726042] [<ffffffff810cb936>] __report_bad_irq+0x36/0xd0
[ 14.726045] [<ffffffff810cbd56>] note_interrupt+0x136/0x1f0
[ 14.726049] [<ffffffff81062c07>] ? local_bh_enable+0x57/0xc0
[ 14.726052] [<ffffffff810caa90>] ? irq_thread_fn+0x50/0x50
[ 14.726054] [<ffffffff810caa0f>] irq_thread+0x1af/0x1e0
[ 14.726057] [<ffffffff810ca860>] ? irq_finalize_oneshot+0x110/0x110
[ 14.726060] [<ffffffff8107e83c>] kthread+0x8c/0xa0
[ 14.726065] [<ffffffff815d33a4>] kernel_thread_helper+0x4/0x10
[ 14.726068] [<ffffffff8107e7b0>] ? kthread_worker_fn+0x190/0x190
[ 14.726071] [<ffffffff815d33a0>] ? gs_change+0x13/0x13
[ 14.726072] handlers:
[ 14.726074] [<ffffffff810ca090>] irq_default_primary_handler threaded [<ffffffff8142fd80>] usb_hcd_irq
[ 14.726080] [<ffffffff810ca090>] irq_default_primary_handler threaded [<ffffffffa001dce0>] ahci_interrupt
[ 14.726093] [<ffffffff810ca090>] irq_default_primary_handler threaded [<ffffffffa1baea40>] snd_hdsp_interrupt
[ 14.726098] Disabling IRQ #16

for me the issue mainly occurs under high cpu load. the issue in [1] is related
to radeon_driver_irq_handler_kms and usb_hcd_irq. however i have mutually
unloaded the ahci, uhci-hcd and snd-hdsp modules and the problem always
occurred sooner or later, so it does not seem to be related to one of the
drivers. however i haven't experienced it before 3.0.

i've currently booted my kernel without the threadirqs options and it seems to
resolve this issue for me, running for a few hours with a rather high cpu load.
however the latency of the system becomes rather high, and i have quite a lot
of audio dropouts (xruns of abour 30ms) ...

how can i help to resolve this isse?

thanks, tim

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