CC: Mika
On Thursday, June 05, 2014 07:46:06 PM Gavin Guo wrote:
> On Thu, May 22, 2014 at 7:36 AM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote:
> > On Wednesday, May 21, 2014 07:53:37 AM Bjorn Helgaas wrote:
> >> On Wed, May 21, 2014 at 3:45 AM, Gavin Guo <gavin.guo@xxxxxxxxxxxxx> wrote:
> >> > Hi Bjorn,
> >> >
> >> > On Wed, May 21, 2014 at 12:54 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote:
> >> >> On Tue, May 20, 2014 at 10:36 PM, Gavin Guo <gavin.guo@xxxxxxxxxxxxx> wrote:
> >> >>> Hi all,
> >> >>>
> >> >>> I have a APIOTEK PCI-to-USB ExpressCard and found that when it is
> >> >>> plugged at cold boot, the card can be detected. But, hotplug cannot
> >> >>> work at run time. The bug may be related to the commit which I
> >> >>> reported last year:
> >> >>>
> >> >>> commit 3f327e39b4b8f760c331bb2836735be6d83fbf53
> >> >>
> >> >> Where is your report from last year? How did you identify this
> >> >> commit? Did you verify that it works correctly with v3.10-rc1, but
> >> >> fails when you add this commit?
> >> >
> >> > The mail about the bug I reported last year is attached. And I'm sorry
> >> > about not describing clearly. This commit is the one to fix the bug
> >> > before. So, I think it will be a clue to find out what's wrong. I've
> >> > built v3.10 and tested it on the platform. It works fine. The bug
> >> > seems like a regression.
> >> >
> >> > I also attached the dmesg of v3.10 which works correctly with hotplug.
> >>
> >> v3.10 contains 3f327e39b4b8 (it appeared in v3.10-rc3). So since it
> >> works correctly in v3.10, that commit is probably not the cause of the
> >> regression.
> >>
> >> So apparently it worked in v3.10 and broke sometime later. Do you
> >> know when it broke?
> >>
> >> We're getting Bus Check events:
> >>
> >> ACPI: \_SB_.PCI0: ACPI_NOTIFY_BUS_CHECK event
> >>
> >> but apparently we aren't handling them correctly. Can you turn on the
> >> debug in the acpi_hotplug_schedule() path and add more if necessary to
> >> if we get to acpi_hotplug_work_fn(), acpi_device_hotplug(), etc.? I'm
> >> not familiar with that path, so either you'll have to narrow it down,
> >> or we can hope that Yinghai or Rafael has some insight.
> >
> > Well, it would be good to create a bug entry for this at bugzilla.kernel.org
> > against ACPI/Config-hotplug and mark it as a regression.
>
> I've completed the bisect and found
> 2d8b1d566a5f4874f4d92361f5cdbb50baa396f8 is the first bad commit. The
> "git bisect log" is also attached.
>
> commit 2d8b1d566a5f4874f4d92361f5cdbb50baa396f8
> Author: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> Date: Sat Jul 13 20:09:59 2013 +0300
>
> ACPI / hotplug / PCI: Get rid of check_sub_bridges()
>
> Now that acpiphp_check_bridge() always enumerates devices behind the
> bridge, there is no need to do that for each sub-bridge anymore like
> it is done in the current ACPI-based PCI hotplug (ACPIPHP) code.
>
> Given this we don't need check_sub_bridges() anymore, so drop that
> function completely.
>
> This also simplifies the ACPIPHP code a bit.
>
> Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>
> :040000 040000 1f3f81404e06c92c01d6848ed7a6c5bffdb5f878
> 4e7ca3e4af42738f90555640cafbb6e6522ceedf M drivers
>
> >
> > Rafael
> >
> >
> >> >>> Author: Yinghai Lu <yinghai@xxxxxxxxxx>
> >> >>> Date: Tue May 7 11:06:03 2013 -0600
> >> >>>
> >> >>> PCI: acpiphp: Re-enumerate devices when host bridge receives Bus Check
> >> >>>
> >> >>> When a PCI host bridge device receives a Bus Check notification, we
> >> >>> must re-enumerate starting with the bridge to discover changes (devices
> >> >>> that have been added or removed).
> >> >>>
> >> >>> Prior to 668192b678 ("PCI: acpiphp: Move host bridge hotplug to
> >> >>> pci_root.c"), this happened in _handle_hotplug_event_bridge(). After that
> >> >>> commit, _handle_hotplug_event_bridge() is not installed for host bridges,
> >> >>> and the host bridge notify handler, _handle_hotplug_event_root() did not
> >> >>> re-enumerate.
> >> >>>
> >> >>> This patch adds re-enumeration to _handle_hotplug_event_root().
> >> >>>
> >> >>> This fixes cases where we don't notice the addition or removal of
> >> >>> PCI devices, e.g., the PCI-to-USB ExpressCard in the bugzilla below.
> >> >>>
> >> >>> Dmesg is attached. The scenario of the dmesg: The PCI-to-USB
> >> >>> ExpressCard is attached at cold boot. Then, you can see that the usb
> >> >>> storage can be detected in the dmesg. Finally, I've done hotplug 2
> >> >>> times to see if it can detect the PCI-to-USB ExpressCard. At the end
> >> >>> of Dmesg, it only has several "ACPI: \_SB_.PCI0: ACPI_NOTIFY_BUS_CHECK
> >> >>> event" and can't detect the card.
> >> >>>
> >> >>> Thanks,
> >> >>> Gavin Guo
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
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> >
> > --
> > I speak only for myself.
> > Rafael J. Wysocki, Intel Open Source Technology Center.
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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