Re: [PATCH V2] PCI: rcar: Add the initialization of PCIe link in resume_noirq

From: Marek Vasut <marek.vasut@gmail.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	linux-pci <linux-pci@vger.kernel.org>,
	Kazufumi Ikeda <kaz-ikeda@xc.jp.nec.com>,
	Gaku Inami <gaku.inami.xw@bp.renesas.com>,
	Marek Vasut <marek.vasut+renesas@gmail.com>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Phil Edworthy <phil.edworthy@renesas.com>,
	Simon Horman <horms+renesas@verge.net.au>,
	Wolfram Sang <wsa@the-dreams.de>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>
Subject: Re: [PATCH V2] PCI: rcar: Add the initialization of PCIe link in resume_noirq
Date: Fri, 22 Mar 2019 13:49:57 +0100	[thread overview]
Message-ID: <f491ae44-37dd-89fa-b4eb-c57715cfbe14@gmail.com> (raw)
In-Reply-To: <CAMuHMdWPZdD3Kat_XJ33ubiiXr4CE_zP7crqrAcbzqOB58V-PQ@mail.gmail.com>

On 3/22/19 1:42 PM, Geert Uytterhoeven wrote:
> Hi Marek,

Hi,

> On Fri, Mar 22, 2019 at 1:33 PM Marek Vasut <marek.vasut@gmail.com> wrote:
>> On 3/22/19 1:29 PM, Geert Uytterhoeven wrote:
>>> On Fri, Mar 22, 2019 at 1:18 PM Lorenzo Pieralisi
>>> <lorenzo.pieralisi@arm.com> wrote:
>>>> On Fri, Mar 22, 2019 at 01:09:13PM +0100, Marek Vasut wrote:
>>>>> On 3/22/19 12:31 PM, Lorenzo Pieralisi wrote:
>>>>>> On Sun, Feb 17, 2019 at 02:24:41PM +0100, marek.vasut@gmail.com wrote:
>>>>>>> From: Kazufumi Ikeda <kaz-ikeda@xc.jp.nec.com>
>>>>>>>
>>>>>>> Reestablish the PCIe link very early in the resume process in case it
>>>>>>> went down to prevent PCI accesses from hanging the bus. Such accesses
>>>>>>> can happen early in the PCI resume process, in the resume_noirq, thus
>>>>>>> the link must be reestablished in the resume_noirq callback of the
>>>>>>> driver.
>>>>>>
>>>>>> This looks like a fix (most likely fixing initial S2R support, please
>>>>>> help me chase the commit ID), should we consider it for stable kernels ?
>>>>>>
>>>>>> Without it I understand S2R is actually broken on platforms with this
>>>>>> host bridge.
>>>>> I don't think this ever worked, so it's hard to find a Fixes: commit for
>>>>> this.
>>>>
>>>> If we want to send it to stable kernels we have to select which versions
>>>> we are covering. I think the only options for a Fixes: tag are either
>>>> the initial S2R support commit for the platforms this driver runs on
>>>> or the initial driver commit that harks back to v3.16 AFAICS.
>>>
>>> This only started to become an issue when support for arm64 platforms
>>> was added, where PSCI may power down the SoC, right?
>>
>> Wouldn't you also hit this on ARM32 LPAE ones ?
> 
> This is about the PCI link issue on system resume, right?

Forget what I said, yes, I mixed this with the MSI 64bit patch.

>>> Hence:
>>> Fixes: e015f88c368da1e6 ("PCI: rcar: Add support for R-Car H3 to pcie-rcar")
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 

-- 
Best regards,
Marek Vasut