From: Kenji Kaneshige <kaneshige.kenji@jp•fujitsu.com>
To: Felix Radensky <felix@embedded-sol•com>
Cc: linux-pci@vger•kernel.org, yinghai@kernel•org,
Alex Chiang <achiang@hp•com>,
"linuxppc-dev@ozlabs•org" <linuxppc-dev@ozlabs•org>
Subject: Re: Problem with PCI bus rescan on 460EX
Date: Wed, 17 Mar 2010 10:03:05 +0900 [thread overview]
Message-ID: <4BA02A49.9050101@jp.fujitsu.com> (raw)
In-Reply-To: <4B9FFAD1.8030309@embedded-sol.com>
Felix Radensky wrote:
> Hello, Kenji-san
>
> Kenji Kaneshige wrote:
>>
>> I misunderstood the problem.
>> My understanding was memory resource was not enabled even though Linux
>> set
>> the Memory Space bit in the command register. But it was not correct. The
>> bridge memory window was marked unused and Linux didn't try to set Memory
>> Space bit in the command register. Current my understanding is as
>> follows.
>> Please correct me if I'm still misunderstanding something.
>>
>> 1) Your BIOS doesn't assign any resource to the bridge if its child PCI
>> hot-plug slot is not occupied.
>>
>> 2) At the boot time, pci_assign_unassigned_resources() try to assign
>> memory resouces to the bridge using pci_bus_assign_resource(), but
>> it was disabled because there are no devices require memory resource.
>>
>> 3) And then pci_assign_unassigned_resouces() calls pci_enable_bridge(),
>> but Memory Space bit in the command register was not set because no
>> memory resource are assigned to the bridge. At the same time,
>> pci_dev->enable_cnt was incremented.
>>
>> 4) At the rescan time, pci_setup_bridge() and pci_enable_bridge() doesn't
>> work because the bridge is already marked "enabled" (i.e.
>> pci_dev->enable_cnt is not zero).
>>
>> I don't have any concrete idea how to fix that so far, but I can say
>> my idea
>> (pcibios_enable_device() should return an error) was wrong.
>>
>>
> I was wandering if setting is_hotplug_bridge property for this bridge
> (e.g. via
> header quirk) can be an acceptable solution. This will allow passing
> hpmemsize
> kernel parameter, to specify the amount of memory to assign to the bridge.
> I've tested this approach and it seems to work.
Looks good to me.
By the way, I think Yinghai's bridge resource reallocation patch series
might help you. It is in Jesse's PCI tree. Please take a look.
Thanks,
Kenji Kaneshige
next prev parent reply other threads:[~2010-03-17 1:03 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4B8E6FA3.70503@embedded-sol.com>
[not found] ` <20100310225100.GB27324@ldl.fc.hp.com>
2010-03-11 7:45 ` Problem with PCI bus rescan on 460EX Felix Radensky
2010-03-11 20:32 ` Benjamin Herrenschmidt
2010-03-11 21:41 ` Felix Radensky
2010-03-11 21:49 ` Benjamin Herrenschmidt
2010-03-11 7:50 ` Felix Radensky
2010-03-12 9:22 ` Kenji Kaneshige
2010-03-12 23:04 ` Felix Radensky
2010-03-15 5:39 ` Kenji Kaneshige
2010-03-15 5:46 ` Benjamin Herrenschmidt
2010-03-15 5:54 ` Benjamin Herrenschmidt
2010-03-15 6:09 ` Felix Radensky
2010-03-15 9:00 ` Kenji Kaneshige
2010-03-15 11:23 ` Felix Radensky
2010-03-16 5:40 ` Kenji Kaneshige
2010-03-16 8:39 ` Felix Radensky
2010-03-16 21:40 ` Felix Radensky
2010-03-17 1:03 ` Kenji Kaneshige [this message]
2010-03-17 7:38 ` Felix Radensky
2010-03-17 7:47 ` Benjamin Herrenschmidt
2010-03-17 7:57 ` Felix Radensky
2010-03-17 23:04 ` Benjamin Herrenschmidt
2010-03-18 0:09 ` Benjamin Herrenschmidt
2010-03-28 9:13 ` Felix Radensky
2010-03-28 9:56 ` Benjamin Herrenschmidt
2010-03-28 13:07 ` Felix Radensky
2010-03-29 0:05 ` Yinghai Lu
2010-03-29 7:01 ` Kenji Kaneshige
2010-03-29 7:35 ` Felix Radensky
2010-03-02 13:27 Felix Radensky
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=4BA02A49.9050101@jp.fujitsu.com \
--to=kaneshige.kenji@jp$(echo .)fujitsu.com \
--cc=achiang@hp$(echo .)com \
--cc=felix@embedded-sol$(echo .)com \
--cc=linux-pci@vger$(echo .)kernel.org \
--cc=linuxppc-dev@ozlabs$(echo .)org \
--cc=yinghai@kernel$(echo .)org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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