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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	Lukas Wunner <lukas@wunner.de>, David Airlie <airlied@linux.ie>,
	Daniel Vetter <daniel@ffwll.ch>,
	Utkarsh Patel <utkarsh.h.patel@intel.com>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	linux-pci@vger.kernel.org
Subject: Re: [PATCH] PCI/PM: Do not generate wakeup event when runtime resuming bus
Date: Mon, 16 Nov 2020 17:06:08 +0100	[thread overview]
Message-ID: <2582211.lb15P8fMpq@kreacher> (raw)
In-Reply-To: <20201113063745.GH2495@lahna.fi.intel.com>

On Friday, November 13, 2020 7:37:45 AM CET Mika Westerberg wrote:
> Hi,
> 
> On Thu, Oct 29, 2020 at 12:24:53PM +0300, Mika Westerberg wrote:
> > When a PCI bridge is runtime resumed from D3cold the underlying bus is
> > walked and the attached devices are runtime resumed as well. However, in
> > addition to that we also generate a wakeup event for these devices even
> > though this actually is not a real wakeup event coming from the
> > hardware.
> > 
> > Normally this does not cause problems but when combined with
> > /sys/power/wakeup_count like using the steps below:
> > 
> >   # count=$(cat /sys/power/wakeup_count)
> >   # echo $count > /sys/power/wakeup_count
> >   # echo mem > /sys/power/state
> > 
> > The system suspend cycle might get aborted at this point if a PCI bridge
> > that was runtime suspended (D3cold) was runtime resumed for any reason.
> > The runtime resume calls pci_wakeup_bus() and that generates wakeup
> > event increasing wakeup_count.
> > 
> > Since this is not a real wakeup event we can prevent the above from
> > happening by removing the call to pci_wakeup_event() in
> > pci_wakeup_bus(). While there rename pci_wakeup_bus() to
> > pci_resume_bus() to better reflect what it does.
> 
> Any comments on this?

I've missed it, sorry.

Now replied with a R-by, thanks!




  reply	other threads:[~2020-11-16 16:12 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-29  9:24 Mika Westerberg
2020-11-13  6:37 ` Mika Westerberg
2020-11-16 16:06   ` Rafael J. Wysocki [this message]
2020-11-16 16:05 ` Rafael J. Wysocki
2020-11-18 21:22 ` Bjorn Helgaas
2020-11-19  7:55   ` Mika Westerberg
2020-11-20  2:27     ` Patel, Utkarsh H

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