Messages in this thread | | | Date | Thu, 11 Jun 2015 16:38:12 -0400 | From | Jarod Wilson <> | Subject | Re: [Update][PATCH] PCIe / hotplug: Drop pointless ACPI-based "slot detection" check |
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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
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