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SubjectRe: [RFC PATCH v5 0/8] introduce PCI bus notifier chain to get rid of the ACPI PCI subdriver interfaces
On 2013-1-29 8:34, Rafael J. Wysocki wrote:
> On Monday, January 28, 2013 01:56:33 PM Bjorn Helgaas wrote:
>> On Fri, Jan 18, 2013 at 9:07 AM, Jiang Liu <liuj97@gmail.com> wrote:
>>> This is an RFC patchset to address review comments in thread at:
>>> https://patchwork.kernel.org/patch/1946851/. The patch just pasts
>>> compilation. If no objection to the new implementation, I will
>>> go on to modify acpiphp driver and conduct tests.
>>>
>>> The main changes from V4 to V5 includes:
>>> 1) introduce a dedicated notifier chain for PCI buses
>>> 2) change pci_slot as built-in driver
>>> 3) unify the way to create/destroy PCI slots
>>> 4) introduce a kernel option to disable PCIe native hotplug
>>>
>>> TODO:
>>> 1) change acpiphp as built-in and unify the way to create/destroy ACPI
>>> based hotplug slots.
>>> 2) change other ACPI PCI subdriver in Yinghai's root bridge hotplug series
>>> to use the PCI bus notifier chain.
>>> 3) Remove the ACPI PCI subdriver interface eventaully.
>>>
>>> Jiang Liu (8):
>>> PCI: make PCI device create/destroy logic symmetric
>>> PCI: split registration of PCI bus devices into two stages
>>> PCI: add a blocking notifier chain for PCI bus addition/removal
>>> ACPI, PCI: avoid building pci_slot as module
>>> PCI, ACPI: hook PCI bus notifications to create/destroy PCI slots
>>> pci_slot: replace printk(KERN_xxx) with pr_xxx()
>>> PCI/PCIe: add "pci=nopciehp" to disable PCIe native hotplug
>>> PCI/PCIe: only claim PME from firmware when CONFIG_PCIE_PME is
>>> enabled
>>>
>>> Documentation/kernel-parameters.txt | 2 +
>>> drivers/acpi/Kconfig | 5 +-
>>> drivers/acpi/internal.h | 5 +
>>> drivers/acpi/pci_root.c | 8 +-
>>> drivers/acpi/pci_slot.c | 217 ++++++++++-------------------------
>>> drivers/acpi/scan.c | 1 +
>>> drivers/pci/bus.c | 26 ++++-
>>> drivers/pci/pci.c | 2 +
>>> drivers/pci/pci.h | 1 +
>>> drivers/pci/pcie/portdrv_core.c | 7 +-
>>> drivers/pci/pcie/portdrv_pci.c | 3 +
>>> drivers/pci/probe.c | 7 +-
>>> drivers/pci/remove.c | 15 +--
>>> include/linux/pci.h | 21 ++++
>>> 14 files changed, 142 insertions(+), 178 deletions(-)
>>
>> I think the problem we're trying to solve is that we don't initialize
>> hot-added devices, correctly, e.g., we don't set up AER, we don't
>> update acpi/pci_slot stuff, we probably don't set up PME etc. We also
>> have similar issues like IOMMU init on powerpc.
>>
>> Notifier chains seem like an unnecessarily complicated way to deal
>> with this. They're great for communicating between modules that stay
>> at arm's length from each other. But that's not the case here --
>> everything is PCI and is quite closely coupled. I think AER, PME,
>> slot, etc., should be initialized directly in pci_device_add() or
>> somewhere nearby.
>
> I agree.
>
>> This might sound a bit radical because it implies some fairly
>> far-reaching changes. It means this code can't be a module (the only
>> one that can be built as a module today is pciehp, and I think
>> everybody agrees that we should make it static as soon as we can
>> figure out the acpiphp/pciehp issue). I think it also means the
>> pcieportdrv concept is of dubious value, since all the services should
>> be known at build-time and we probably don't need a registration
>> interface for them.
>
> It is of dubious value regardless. It just adds complexity for no gain.
> Moreover, these things are in fact not mutually independent.
>
> I've had a lot of headaches trying to work around that when I was working
> on PME support and later on _OSC for root bridges. Let's just take that
> stuff away once and for good. :-)
Hi Bjorn and Rafael,
Thanks for advice. We will go this direction to change those modules
as built-in.
Regards!
Gerry

>
> Thanks,
> Rafael
>
>




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