[PATCH v2 5/5] PCI/powerpc/eeh: Add pcibios hooks for preparing to rescan

[Sergey Miroshnichenko]

On 9/12/18 1:39 PM,  wrote:
> On Mon, 2018-09-10 at 19:00 +0300, Sergey Miroshnichenko wrote:
>>
>> Yes, missing a real EEH event is possible, unfortunately, and it is
>> indeed worth mentioning.
>>
>> To reduce this probability the next patchset I'll post in a few days
>> among other things puts all the affected device drivers to pause during
>> rescan, mainly because of moving BARs and bridge windows, but it will
>> also help here a bit.
> 
> How do you deal with moving BARs etc... within the segmenting
> restrictions of EEH ?
> 

Actually, [un]fortunately, we haven't encountered any segmenting issues
yet, but to move BARs we are using the same existing mechanism in Linux
kernel that re-enumerated the PCIe topology during startup with
"pci=realloc" and PCI_REASSIGN_ALL_BUS. What restrictions must be broken
to provoke a segmenting event?

Are there any other limitations on segmenting besides keeping all the
BARs of the PHB within its huge M32+M64 segments which are 2GiB+4GiB on
our setup?

> It's a horrible mess right now and I don't know if the current code can
> even work properly to be honest.
> 
> Cheers,
> Ben.
> 
> 

Best regards,
Serge