From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Subject: Re: [PATCH] PCI: Power on bridges before scanning new devices
Date: Wed, 25 May 2016 02:03:06 +0200
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References: <20160519231234.GB1785@al> <20160524125323.GE1789@lahna.fi.intel.com> <20160524211309.GH1789@lahna.fi.intel.com>
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To: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>, Bjorn Helgaas <bhelgaas@google.com>, Peter Wu <peter@lekensteyn.nl>, Lukas Wunner <lukas@wunner.de>, linux-pci@vger.kernel.org, linux-pm@vger.kernel.org, Valdis Kletnieks <valdis.kletnieks@vt.edu>, Dave Airlie <airlied@gmail.com>

On Wednesday, May 25, 2016 12:13:09 AM Mika Westerberg wrote:
> On Tue, May 24, 2016 at 03:53:23PM +0300, Mika Westerberg wrote:
> > > I dropped "ACPI / hotplug / PCI: Runtime resume bridge before rescan"
> > > on the assumption that "PCI: Power on bridges before scanning new
> > > devices" is sufficient to cover both the ACPI and the generic PCi
> > > rescan cases, but I'd like some reassurance about that.
> > 
> > I agree with your reasoning that the patch should not be needed anymore.
> > However, I have the machine which needed that patch at home so I'm not
> > able to test it now. I'll do that later today when I get back home.
> 
> I tried now on my Lenovo Yoga 900 laptop and unfortunately "PCI: Power
> on bridges before scanning new devices" seems not to be enough. This
> machine has SD-card reader connected to one PCIe port and once I unload
> the sdhci-pci driver and enable runtime PM for the device, next system
> suspend/resume cycle loses the SD-card reader PCI device.
> 
> I will investigate more tomorrow -- it is getting late here.
> 
> Anyway, maybe it is safer to postpone this series for v4.8 to give it
> more testing time in -next.

Agreed.

I don't see a compelling enough reason to rush these changes into 4.7
and it looks like there are gaps in our understanding of the issues
involved.

Thanks,
Rafael