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Date: Fri, 6 Jan 2012 05:24:08 -0800
From: Greg KH <greg@kroah.com>
To: MUNEDA Takahiro <muneda.takahiro@jp.fujitsu.com>
Cc: linux-pci@vger.kernel.org
Subject: Re: [PATCH] Add pcie_hp=nomsi to disable MSI for pciehp driver
Message-ID: <20120106132408.GB8989@kroah.com>
References: <20120106095637.16292.29895.sendpatchset@dhcp-189-101.bos.redhat.com>
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On Fri, Jan 06, 2012 at 04:56:37AM -0500, MUNEDA Takahiro wrote:
> Not to use MSI/MSI-X for pciehp, add a kernel parameter, pcie_hp=nomsi.
> 
> In my environment, while shutting down, following stack trace is shown
> sometimes.
> 
>   irq 16: nobody cared (try booting with the "irqpoll" option)
>   Pid: 1081, comm: reboot Not tainted 3.2.0 #1
>   Call Trace:
>    <IRQ>  [<ffffffff810cec1d>] __report_bad_irq+0x3d/0xe0
>    [<ffffffff810cee1c>] note_interrupt+0x15c/0x210
>    [<ffffffff810cc485>] handle_irq_event_percpu+0xb5/0x210
>    [<ffffffff810cc621>] handle_irq_event+0x41/0x70
>    [<ffffffff810cf675>] handle_fasteoi_irq+0x55/0xc0
>    [<ffffffff81015356>] handle_irq+0x46/0xb0
>    [<ffffffff814fbe9d>] do_IRQ+0x5d/0xe0
>    [<ffffffff814f146e>] common_interrupt+0x6e/0x6e
>    [<ffffffff8106b040>] ? __do_softirq+0x60/0x210
>    [<ffffffff8108aeb1>] ? hrtimer_interrupt+0x151/0x240
>    [<ffffffff814fb5ec>] call_softirq+0x1c/0x30
>    [<ffffffff810152d5>] do_softirq+0x65/0xa0
>    [<ffffffff8106ae9d>] irq_exit+0xbd/0xe0
>    [<ffffffff814fbf8e>] smp_apic_timer_interrupt+0x6e/0x99
>    [<ffffffff814f9e5e>] apic_timer_interrupt+0x6e/0x80
>    <EOI>  [<ffffffff814f0fb1>] ? _raw_spin_unlock_irqrestore+0x11/0x20
>    [<ffffffff812629fc>] pci_bus_write_config_word+0x6c/0x80
>    [<ffffffff81266fc2>] pci_intx+0x52/0xa0
>    [<ffffffff8127de3d>] pci_intx_for_msi+0x1d/0x30
>   [<ffffffff8127e4fb>] pci_msi_shutdown+0x7b/0x110
>    [<ffffffff81269d34>] pci_device_shutdown+0x34/0x50
>    [<ffffffff81326c4f>] device_shutdown+0x2f/0x140
>    [<ffffffff8107b981>] kernel_restart_prepare+0x31/0x40
>    [<ffffffff8107b9e6>] kernel_restart+0x16/0x60
>    [<ffffffff8107bbfd>] sys_reboot+0x1ad/0x220
>    [<ffffffff814f4b90>] ? do_page_fault+0x1e0/0x460
>    [<ffffffff811942d0>] ? __sync_filesystem+0x90/0x90
>    [<ffffffff8105c9aa>] ? __cond_resched+0x2a/0x40
>    [<ffffffff814ef090>] ? _cond_resched+0x30/0x40
>    [<ffffffff81169e17>] ? iterate_supers+0xb7/0xd0
>    [<ffffffff814f9382>] system_call_fastpath+0x16/0x1b
>   handlers:
>   [<ffffffff8138a0f0>] usb_hcd_irq
>   [<ffffffff8138a0f0>] usb_hcd_irq
>   [<ffffffff8138a0f0>] usb_hcd_irq
>   Disabling IRQ #16
> 
> An un-wanted interrupt is generated when PCI driver switches from
> MSI/MSI-X to INTx while shutting down the device.  The interrupt does
> not happen if MSI/MSI-X is not used on the device.
> I confirmed that this problem does not happen if pcie_hp=nomsi was
> specified and hotplug operation worked fine as usual.
> 
> Signed-off-by: MUNEDA Takahiro <muneda.takahiro@jp.fujitsu.com>

There's no way to figure this out automatically?  How about just doing
this for the PCI ids of your hardware?

Adding a boot option is a pain, as users will not know they need to do
it, and distros will not know they need to add it to their images.
Please try to do this in an automated way if at all possible.

thanks,

greg k-h