From: poza@codeaurora.org
To: Keith Busch <keith.busch@intel.com>
Cc: Sinan Kaya <okaya@codeaurora.org>,
Linux PCI <linux-pci@vger.kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>
Subject: Re: [PATCH] PCI/AER: Prevent runtime power management during recovery
Date: Tue, 12 Jun 2018 20:46:12 +0530 [thread overview]
Message-ID: <24bc5664ce1c0ac40b48eb6d757e19aa@codeaurora.org> (raw)
In-Reply-To: <20180612144443.GA3142@localhost.localdomain>
On 2018-06-12 20:14, Keith Busch wrote:
> On Tue, Jun 12, 2018 at 01:21:53PM +0530, poza@codeaurora.org wrote:
>> On 2018-06-12 10:10, Sinan Kaya wrote:
>> > On 6/11/2018 6:29 PM, Keith Busch wrote:
>> > > A bridge that supports D3 but not hotplug will be subject to runtime
>> > > power management placing it in a non-operation power state if it
>> > > doesn't
>> > > have any devices attached. This patch will prevent this power
>> > > management
>> > > during error recovery so that the rescan at the end may be successful.
>> >
>> > If there is no card connected, why would the bridge observe a fatal
>> > error?
>>
>> fatal error could be coming from anywhere let us say below RootPort..
>> and RP observes it and decides to take the tree down....
>> Is that the case Keith is talking about ?
>
> Right, the err fatal handling removes all the devices below a bridge,
> making that bridge allowed for run time d3.
>
>> Why will re-enumeration be a problem even if runtime PM is active ?
>> I assume that enumeration will get bridge out of D3.
>
> That doesn't seem to be the case.
reset_link(udev, service); will initiate SBR, and which should do hot
reset the bridge and bring it out of D3 !
but it seems even SBR is not doing it for you.
Although I am not sure if the EP has to be designed to reset its config
space upon SBR.. even if they are, some just might not do it all
correctly !
The code looks okay to me anyway.
Reviewed-by: Oza Pawandeep <poza@codeaurora.org>
next prev parent reply other threads:[~2018-06-12 15:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-11 22:29 [PATCH] PCI/AER: Prevent runtime power management during recovery Keith Busch
2018-06-12 4:40 ` Sinan Kaya
2018-06-12 7:51 ` poza
2018-06-12 14:44 ` Keith Busch
2018-06-12 15:16 ` poza [this message]
2018-06-30 19:58 ` Bjorn Helgaas
2018-07-01 11:51 ` Lukas Wunner
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