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
>> the body of a message to majordomo@xxxxxxxxxxxxxxx
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
> --
> I speak only for myself.
> Rafael J. Wysocki, Intel Open Source Technology Center.
# bad: [272b98c6455f00884f0350f775c5342358ebb73f] Linux 3.12-rc1
# good: [6e4664525b1db28f8c4e1130957f70a94c19213e] Linux 3.11
# good: [39772038ea93e85ea4f1307ec9c1f48a063d89a0] PCI: Assign resources for hot-added host bridge more aggressively
# good: [3dc48af310709b85d07c8b0d3aa8f1ead02829d3] PCI/ACPI: Fix _OSC ordering to allow PCIe hotplug use when available
git bisect start 'v3.12-rc1' 'v3.11' '39772038ea93e85ea4f1307ec9c1f48a063d89a0' '3dc48af310709b85d07c8b0d3aa8f1ead02829d3' '--'
# bad: [57d730924d5cc2c3e280af16a9306587c3a511db] Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
git bisect bad 57d730924d5cc2c3e280af16a9306587c3a511db
# bad: [357397a14117f0c2eeafcac06a1f8412a02aa6af] Merge branch 'for-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata
git bisect bad 357397a14117f0c2eeafcac06a1f8412a02aa6af
# good: [91121c103ae93ef117e58712786864270d7f488e] staging: dwc2: make dwc2_core_params documentation more complete
git bisect good 91121c103ae93ef117e58712786864270d7f488e
# good: [1d1fdd95df681f0c065d90ffaafa215a0e8825e2] Merge tag 'char-misc-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
git bisect good 1d1fdd95df681f0c065d90ffaafa215a0e8825e2
# good: [d472d9d98b463dd7a04f2bcdeafe4261686ce6ab] lockref: Relax in cmpxchg loop
git bisect good d472d9d98b463dd7a04f2bcdeafe4261686ce6ab
# bad: [7a330a5416de9240c93a6987e11cb32b581d3263] Merge branch 'pm-cpufreq'
git bisect bad 7a330a5416de9240c93a6987e11cb32b581d3263
# bad: [8462d9df9d5033da4d25e59016b1e7a9d94a1f22] Merge branch 'acpi-bind'
git bisect bad 8462d9df9d5033da4d25e59016b1e7a9d94a1f22
# bad: [abe5430e9d5314190ca571b3bfc0c42000634378] Merge branch 'acpi-pci-hotplug'
git bisect bad abe5430e9d5314190ca571b3bfc0c42000634378
# good: [c8ebcf1ff91a8f64b09c4df0ee21ae80a953c39c] ACPI / hotplug / PCI: Pass hotplug context objects to event handlers
git bisect good c8ebcf1ff91a8f64b09c4df0ee21ae80a953c39c
# good: [5c8d0e1dc475f0f35b5a774c92c68c3f7dbd3f5f] ACPI / hotplug / PCI: Do not queue up event handling work items in vain
git bisect good 5c8d0e1dc475f0f35b5a774c92c68c3f7dbd3f5f
# good: [a1d0abcea845730c4ff2f47897e28c2f11c79d4f] ACPI / hotplug / PCI: Redefine enable_device() and disable_device()
git bisect good a1d0abcea845730c4ff2f47897e28c2f11c79d4f
# bad: [1aaac07112f04068d7e2fc47bb435cfd4f9d5468] ACPI / hotplug / PCI: Fix NULL pointer dereference in cleanup_bridge()
git bisect bad 1aaac07112f04068d7e2fc47bb435cfd4f9d5468
# bad: [2d8b1d566a5f4874f4d92361f5cdbb50baa396f8] ACPI / hotplug / PCI: Get rid of check_sub_bridges()
git bisect bad 2d8b1d566a5f4874f4d92361f5cdbb50baa396f8
# good: [ff181e5a4f6b536e5f3f1601cd5c54e792cd9abc] ACPI / hotplug / PCI: Clean up bridge_mutex usage
git bisect good ff181e5a4f6b536e5f3f1601cd5c54e792cd9abc
