From: Yinghai Lu <yinghai@kernel.org>
To: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>,
Alex Chiang <achiang@hp.com>, Ingo Molnar <mingo@elte.hu>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org
Subject: Re: [PATCH 10/11] pciehp: add support for bridge resource reallocation
Date: Sun, 17 Jan 2010 14:35:35 -0800 [thread overview]
Message-ID: <4B5390B7.5000801@kernel.org> (raw)
In-Reply-To: <20100117093418.6d545b43@jbarnes-piketon>
On 01/17/2010 09:34 AM, Jesse Barnes wrote:
> On Sat, 16 Jan 2010 16:14:31 -0700
> Bjorn Helgaas <bjorn.helgaas@hp.com> wrote:
>
>> On Sat, 2010-01-16 at 01:34 -0800, Yinghai Lu wrote:
>>> On 01/15/2010 08:59 PM, Alex Chiang wrote:
>>>> * Yinghai Lu <yinghai@kernel.org>:
>>>>> From: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
>>>>>
>>>>> With this patch, pciehp driver try to clear PCI bridge resources
>>>>> to parent bridge (root port or switch downstream port) of the
>>>>> slot
>>>>>
>>>>> so we can shrink pci bridge resource for those port
>>>>>
>>>>> This feature is enabled when 'pciehp_realloc' option is
>>>>> specified.
>>>>>
>>>>> -v2: make it could be appiled after Yinghai patchset that touch
>>>>> pci bridge resource also remove poweron check, because
>>>>> pci_bridge_release_res will check child at first
>>>>
>>>> Same comment as my earlier patch. Why not just make this the
>>>> default behavior, instead of introducing yet another command line
>>>> parameter for users to guess at?
>>>
>>> it will break Eric's setup/
>>
>> I think this is a clue that we don't understand the problem well
>> enough yet.
>>
>> I'm opposed to adding kernel parameters for this sort of thing. It is
>> unreasonable to expect users to figure out whether they need to use
>> this parameter or not.
>>
>> Special-case switches like this make it much harder to maintain the
>> code in the future.
>
> Agreed. Yinghai, what's wrong in the new reassignment code that
> causes Eric's setup to break? Can we just fix that instead and enable
> reallocation by default?
no.
Eric's setup is:
hot plug one addon card into one hotplug slots and new addon cards have more hot plug slots.
SLOTA will have SLOT B, SLOT C, and SLOT D as children. and not devices in SLOTB/C/D at first.
with the pciehp_realloc is specified, the SLOTA will not get any device assigned, and later
if put devices in SLOTB/SLOTC/SLOTD, will not get resource for those devices.
and we can not go above to update SLOT A, because: some devices on SLOTB could already have driver loaded.
if you don't like pciehp_realloc at this point, please only apply 1-8 and 11.
Thanks
Yinghai Lu
next prev parent reply other threads:[~2010-01-17 22:37 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-16 2:41 [PATCH 00/11] pci: update pci bridge resources Yinghai Lu
2010-01-16 2:41 ` [PATCH 01/11] pci: add pci_bridge_release_unused_res and pci_bus_release_unused_bridge_res Yinghai Lu
2010-01-16 3:57 ` Alex Chiang
2010-01-16 10:10 ` Yinghai Lu
2010-01-16 2:41 ` [PATCH 02/11] pci: add failed_list to record failed one for pci_bus_assign_resources Yinghai Lu
2010-01-16 4:05 ` Alex Chiang
2010-01-16 2:41 ` [PATCH 03/11] pci: reject mmio range start from 0 on pci_bridge read Yinghai Lu
2010-01-16 4:20 ` Alex Chiang
2010-01-16 2:41 ` [PATCH 04/11] pci: don't shrink bridge resources Yinghai Lu
2010-01-16 2:41 ` [PATCH 05/11] pci: update bridge res to get more big range in pci assign unssign Yinghai Lu
2010-01-16 4:38 ` Alex Chiang
2010-01-16 2:41 ` [PATCH 06/11] pci: introduce pci_assign_unassigned_bridge_resources Yinghai Lu
2010-01-16 4:47 ` Alex Chiang
2010-01-16 2:41 ` [PATCH 07/11] pci: pciehp clean flow in pciehp_configure_device Yinghai Lu
2010-01-16 2:41 ` [PATCH 08/11] pci: pciehp second try to get big range for pcie devices Yinghai Lu
2010-01-16 4:52 ` Alex Chiang
2010-01-16 2:41 ` [PATCH 09/11] pci: pci_bridge_release_res Yinghai Lu
2010-01-16 4:57 ` Alex Chiang
2010-01-16 2:42 ` [PATCH 10/11] pciehp: add support for bridge resource reallocation Yinghai Lu
2010-01-16 4:59 ` Alex Chiang
2010-01-16 5:22 ` Yinghai Lu
2010-01-16 9:34 ` Yinghai Lu
2010-01-16 23:14 ` Bjorn Helgaas
2010-01-17 17:34 ` Jesse Barnes
2010-01-17 22:35 ` Yinghai Lu [this message]
2010-01-16 2:42 ` [PATCH 11/11] pci: set PCI_PREF_RANGE_TYPE_64 in pci_bridge_check_ranges Yinghai Lu
-- strict thread matches above, loose matches on Subject: below --
2010-01-16 11:07 [PATCH 00/11] pci: update pci bridge resources Yinghai Lu
2010-01-16 11:07 ` [PATCH 10/11] pciehp: add support for bridge resource reallocation Yinghai Lu
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