From: Jarod Wilson <jarod@redhat.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-kernel@vger.kernel.org, Len Brown <lenb@kernel.org>,
linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org
Subject: Re: [Update][PATCH] PCIe / hotplug: Drop pointless ACPI-based "slot detection" check
Date: Thu, 11 Jun 2015 16:38:12 -0400 [thread overview]
Message-ID: <5579F1B4.9000206@redhat.com> (raw)
In-Reply-To: <5579BFD9.9040904@redhat.com>
On 6/11/2015 1:05 PM, Jarod Wilson wrote:
> On 5/21/2015 9:21 PM, Rafael J. Wysocki wrote:
>> On Thursday, May 21, 2015 11:11:46 AM Bjorn Helgaas wrote:
>>> On Tue, May 19, 2015 at 03:27:58PM +0200, Rafael J. Wysocki wrote:
>>>> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>>>
>>>> Jarod Wilson reports that the expresscard hotplug setup doesn't work
>>>> on HP ZBook G2. The problem turns out to be the ACPI-based "slot
>>>> detection" code called from pciehp_probe() which tries to use some
>>>> questionable heuristics based on what ACPI objects are present for
>>>> the PCIe port device at hand to figure out whether or not to register
>>>> a hotplug slot for that port.
>>>>
>>>> That code is used if there is at least one PCIe port having an ACPI
>>>> device configuration object related to hotplug (such as _EJ0 or _RMV)
>>>> and the Thunderbolt port on the affected machine has _RMV. Of course,
>>>> Thunderbolt and PCIe native hotplug need not be mutually exclusive
>>>> (as they aren't on the machine in question), so that rule is simply
>>>> incorrect.
>>>>
>>>> Moreover, the ACPI-based "slot detection" check does not add any
>>>> value if pciehp_probe() is called at all and the service type of the
>>>> device object it has been called for is PCIE_PORT_SERVICE_HP, because
>>>> PCIe hotplug services are only registered if the _OSC handshake in
>>>> acpi_pci_root_add() allows the kernel to control the PCIe native
>>>> hotplug feature. No more checks need to be carried out to decide
>>>> whether or not to register a native PCIe hotlug slot in that case.
>>>>
>>>> For the above reasons, make pciehp_probe() check if it has been
>>>> called for the right service type and drop the pointless ACPI-based
>>>> "slot detection" check from it. Also remove the entire code whose
>>>> only user is that check (the entire pciehp_acpi.c file goes away
>>>> as a result) and drop function headers related to it from the
>>>> internal PCIeHP header file.
>>>>
>>>> Link: http://marc.info/?t=143163219300002&r=1&w=2
>>>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=98581
>>>> Reported-by: Jarod Wilson <jarod@redhat.com>
>>>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>>
>>> This is awesome! Applied to pci/hotplug for v4.2, with Jarod's
>>> reviewed/tested-by.
>>
>> Thanks!
>
> Looks like I didn't test enough. I can't explain WHY, but with this
> applied, now thunderbolt hot unplug of a network adapter goes haywire,
> where prior to the patch, it worked just fine. Still looking into it...
Filed bug, dmesg spew can be found in the bug.
https://bugzilla.kernel.org/show_bug.cgi?id=99841
--
Jarod Wilson
jarod@redhat.com
next prev parent reply other threads:[~2015-06-11 20:40 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-14 19:33 [PATCH] pci/hotplug: work-around for missing _RMV on HP ZBook G2 Jarod Wilson
2015-05-16 14:37 ` Bjorn Helgaas
2015-05-16 14:41 ` Bjorn Helgaas
2015-05-18 0:26 ` Rafael J. Wysocki
2015-05-18 14:33 ` Jarod Wilson
2015-05-18 16:17 ` Jarod Wilson
2015-05-18 20:45 ` Jarod Wilson
2015-05-18 23:06 ` Rafael J. Wysocki
2015-05-19 3:06 ` Jarod Wilson
2015-05-19 11:36 ` Rafael J. Wysocki
2015-05-19 11:43 ` [PATCH] PCIe / hotplug: Drop pointless ACPI-based "slot detection" check Rafael J. Wysocki
2015-05-19 12:42 ` Jarod Wilson
2015-05-19 13:29 ` Rafael J. Wysocki
2015-05-19 13:27 ` [Update][PATCH] " Rafael J. Wysocki
2015-05-19 14:40 ` Jarod Wilson
2015-05-21 16:11 ` Bjorn Helgaas
2015-05-22 1:21 ` Rafael J. Wysocki
2015-06-11 17:05 ` Jarod Wilson
2015-06-11 20:38 ` Jarod Wilson [this message]
2015-06-11 21:16 ` Rafael J. Wysocki
2015-06-11 21:49 ` Jarod Wilson
2015-05-18 21:57 ` [PATCH] pci/hotplug: work-around for missing _RMV on HP ZBook G2 Rafael J. Wysocki
2015-05-18 14:30 ` Jarod Wilson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5579F1B4.9000206@redhat.com \
--to=jarod@redhat.com \
--cc=bhelgaas@google.com \
--cc=lenb@kernel.org \
--cc=linux-acpi@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=rjw@rjwysocki.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).