Linux PCI subsystem development
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From: Bjorn Helgaas <helgaas@kernel.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Marek Vasut <marek.vasut@gmail.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>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Simon Horman <horms+renesas@verge.net.au>,
	Wolfram Sang <wsa+renesas@sang-engineering.com>,
	stable <stable@vger.kernel.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Phil Edworthy <phil.edworthy@renesas.com>,
	Wolfram Sang <wsa@the-dreams.de>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>
Subject: Re: [PATCH V3] PCI: rcar: Add the initialization of PCIe link in resume_noirq()
Date: Thu, 28 Mar 2019 13:59:13 -0500	[thread overview]
Message-ID: <20190328185913.GC24180@google.com> (raw)
In-Reply-To: <CAMuHMdVsJ1MW40ABuieLq7F6=zG_btAHZUr82Z4_pPVem3h=jA@mail.gmail.com>

On Thu, Mar 28, 2019 at 03:59:11PM +0100, Geert Uytterhoeven wrote:
> On Thu, Mar 28, 2019 at 3:18 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
> > On Mon, Mar 25, 2019 at 08:43:19PM +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, as early as the
> > > SUSPEND_RESUME_NOIRQ step, thus the link must be reestablished in the
> > > driver resume_noirq() callback.
> > >
> > > Fixes: e015f88c368d ("PCI: rcar: Add support for R-Car H3 to pcie-rcar")
> >
> > I'm fine with the fix itself, but since e015f88c368d appeared more
> > than two years ago in v4.5, the justification for merging this after
> > the merge window is a little weak.
> 
> V1 of this fix was posted in November 2017, but IIRC, the series became
> the target of some bike-shedding...
> 
> > Is there a more recent change that exposed this problem?  The usual
> > situation is that we merged something during the v5.1 merge window
> > that caused a regression, and we're now fixing that before v5.1 final.
> 
> There are several reasons most people couldn't even run suspend/resume
> cycles on their systems:
>   1. Early releases of the affected boards came with firmware revisions with
>      non-functional PSCI system suspend,
>   2. Preparing the PMIC for suspend required ugly assistance from i2cset
>      in userspace, until the Linux driver learned to take care of that itself
>      in v4.18/v4.19.
> 
> I guess the fix can survive postponing to v5.2, though...

Ok, I'll merge it to -next for v5.2, thanks.

Bjorn

  reply	other threads:[~2019-03-28 18:59 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-25 19:43 [PATCH V3] PCI: rcar: Add the initialization of PCIe link in resume_noirq() marek.vasut
2019-03-26  7:57 ` Geert Uytterhoeven
2019-03-26 11:24 ` Lorenzo Pieralisi
2019-03-28 14:18 ` Bjorn Helgaas
2019-03-28 14:43   ` Lorenzo Pieralisi
2019-03-28 14:59   ` Geert Uytterhoeven
2019-03-28 18:59     ` Bjorn Helgaas [this message]
2019-03-29  9:52       ` Marek Vasut

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