Re: [PATCH v7] PCI: Try best to allocate pref mmio 64bit above 4g

[Wei Yang <weiyang@linux.vnet.ibm.com>]

On Tue, Apr 08, 2014 at 10:18:48AM +0300, Or Gerlitz wrote:
>On 08/04/2014 05:57, Guo Chao wrote:
>>On Fri, Apr 04, 2014 at 04:43:27PM -0600, Bjorn Helgaas wrote:
>>>On Fri, Mar 7, 2014 at 1:08 PM, Yinghai Lu <yinghai@kernel.org> wrote:
>>>>When one of children resources does not support MEM_64, MEM_64 for
>>>>bridge get reset, so pull down whole pref resource on the bridge under 4G.
>>>>
>>>>If the bridge support pref mem 64, will only allocate that with pref mem64 to
>>>>children that support it.
>>>>For children resources if they only support pref mem 32, will allocate them
>>>>from non pref mem instead.
>>>>
>>>>If the bridge only support 32bit pref mmio, will still have all children pref
>>>>mmio under that.
>>>>
>>>>-v2: Add release bridge res support with bridge mem res for pref_mem children res.
>>>>-v3: refresh and make it can be applied early before for_each_dev_res patchset.
>>>>-v4: fix non-pref mmio 64bit support found by Guo Chao.
>>>>-v7: repost as ibm's powerpc system work again when
>>>>     1. petiboot boot kernel have this patch.
>>>>     2. or mellanox driver added new .shutdown member.
>>>>     discussion could be found at:
>>>>          http://marc.info/?t=138968064500001&r=1&w=2
>>>I think this fixes some sort of bug, and I suppose if I spent a few
>>>hours decoding the discussion you mention (the 44 message-long
>>>"mlx4_core probe error after applying Yinghai's patch" discussion), I
>>>might be able to figure out what it is.
>>>
>>The result of 44 message-long discussion is: the Mellanox card's failure is
>>due to a bug in its driver instead of this patch.
>
>
>So just to make sure we're on the same page -- fixing the bug is
>carried out through netdev, e.g this 3.14-rc8
>upstream commit 97a5221 "net/mlx4_core: pass
>pci_device_id.driver_data to __mlx4_init_one during reset"
>and now this one more fix which is under discussion
>http://marc.info/?l=linux-pci&m=139675010015646&w=2, right?

No, this one http://marc.info/?l=linux-pci&m=139675010015646&w=2 is another
bug in mlx4 driver, missing a proper pci_dev_data in mlx4_init_one.

The bug discussing in this thread is the driver "forget" to release the
"owner" during kexec. So this device couldn't be usded after kexec.

>
>
>
>>
>>The patch refines the logic of using prefetchable window, so that 64-bit
>>prefetchable BARs have a chance to be really prefetchable. It does not fix
>>any bugs, instead, it exposes one.

-- 
Richard Yang
Help you, Help me