Arthur Marsh wrote on 06/09/15 21:07:
> Arthur Marsh wrote on 06/09/15 18:34:
>> Arthur Marsh wrote on 06/09/15 15:58:
>>> Hi, I'm seeing the following on post 4.2 kernels, am currently bisecting
>>> to find where it started:
>
> First kernel in the bisection that worked without needing irqpoll:
>
> [   73.751482] EATA0: IRQ 10 mapped to IO-APIC IRQ 17.
> [   73.776711] EATA/DMA 2.0x: Copyright (C) 1994-2003 Dario Ballabio.
> [   73.802005] EATA config options -> tm:1, lc:y, mq:16, rs:y, et:n,
> ip:n, ep:n, pp:y.
> [   73.829175] EATA0: 2.0C, PCI 0xd890, IRQ 17, BMST, SG 122, MB 64.
> [   73.855552] EATA0: wide SCSI support enabled, max_id 16, max_lun 8.
> [   73.881125] EATA0: SCSI channel 0 enabled, host target ID 7.

After a git bisect, I get:

git bisect good
991de2e59090e55c65a7f59a049142e3c480f7bd is the first bad commit
commit 991de2e59090e55c65a7f59a049142e3c480f7bd
Author: Jiang Liu <jiang.liu@linux.intel.com>
Date:   Wed Jun 10 16:54:59 2015 +0800

     PCI, x86: Implement pcibios_alloc_irq() and pcibios_free_irq()

     To support IOAPIC hotplug, we need to allocate PCI IRQ resources on 
demand
     and free them when not used anymore.

     Implement pcibios_alloc_irq() and pcibios_free_irq() to dynamically
     allocate and free PCI IRQs.

     Remove mp_should_keep_irq(), which is no longer used.

     [bhelgaas: changelog]
     Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
     Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
     Acked-by: Thomas Gleixner <tglx@linutronix.de>

:040000 040000 765e2d5232d53247ec260b34b51589c3bccb36ae 
f680234a27685e94b1a35ae2a7218f8eafa9071a M      arch
:040000 040000 d55a682bcde72682e883365e88ad1df6186fd54d 
f82c470a04a6845fcf5e0aa934512c75628f798d M      drivers

I'm happy to supply more details if needed.

Regards,

Arthur.