[PATCH v2] powerpc/powernv: Add pci_reset_phbs parameter to issue a PHB reset

[Guilherme G. Piccoli]

On 11/16/2017 01:49 AM, Balbir Singh wrote:
> On Thu, Oct 26, 2017 at 2:27 AM, Guilherme G. Piccoli
> <gpiccoli at linux.vnet.ibm.com> wrote:
>> During a kdump kernel boot in PowerPC, we request a reset of the PHBs
>> to the FW. It makes sense, since if we are booting a kdump kernel it
>> means we had some trouble before and we cannot rely in the adapters'
>> health; they could be in a bad state, hence the reset is needed.
>>
>> But this reset is useful not only in kdump - there are situations,
>> specially when debugging drivers, that we could break an adapter in
>> a way it requires such reset. One can tell to just go ahead and
>> reboot the machine, but happens that many times doing kexec is much
>> faster, and so preferable than a full power cycle.
>>
>> This patch adds the pci_reset_phbs parameter to perform such reset
>> when desired by the user.
>>
> 
> Do we care to reset specific phbs or all of them? I guess all based on
> your description.

Exactly Balbir, it does reset all of them. We could add such
granularity, but I don't see much usability..
But if somebody feels it's useful, we can change...

Thanks!


> 
> Balbir Singh.
>