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From: Bjorn Helgaas <helgaas@kernel.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Linux PCI <linux-pci@vger.kernel.org>,
	Linux PM <linux-pm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Mika Westerberg <mika.westerberg@linux.intel.com>
Subject: Re: [PATCH] PCI / PM: Do not clear state_saved for devices that remain suspended
Date: Tue, 22 May 2018 17:01:49 -0500	[thread overview]
Message-ID: <20180522220149.GB22385@bhelgaas-glaptop.roam.corp.google.com> (raw)
In-Reply-To: <11415287.ki0m5Bqgns@aspire.rjw.lan>

On Fri, May 18, 2018 at 10:17:42AM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> The state_saved flag should not be cleared in pci_pm_suspend() if the
> given device is going to remain suspended, or the device's config
> space will not be restored properly during the subsequent resume.
> 
> Namely, if the device is going to stay in suspend, both the late
> and noirq callbacks return early for it, so if its state_saved flag
> is cleared in pci_pm_suspend(), it will remain unset throughout the
> remaining part of suspend and resume and pci_restore_state() called
> for the device going forward will return without doing anything.
> 
> For this reason, change pci_pm_suspend() to only clear state_saved
> if the given device is not going to remain suspended.  [This is
> analogous to what commit ae860a19f37c (PCI / PM: Do not clear
> state_saved in pci_pm_freeze() when smart suspend is set) did for
> hibernation.]
> 
> Fixes: c4b65157aeef (PCI / PM: Take SMART_SUSPEND driver flag into account)
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

I assume you'll take this one, too.

> ---
>  drivers/pci/pci-driver.c |    5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> Index: linux-pm/drivers/pci/pci-driver.c
> ===================================================================
> --- linux-pm.orig/drivers/pci/pci-driver.c
> +++ linux-pm/drivers/pci/pci-driver.c
> @@ -753,10 +753,11 @@ static int pci_pm_suspend(struct device
>  	 * better to resume the device from runtime suspend here.
>  	 */
>  	if (!dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND) ||
> -	    !pci_dev_keep_suspended(pci_dev))
> +	    !pci_dev_keep_suspended(pci_dev)) {
>  		pm_runtime_resume(dev);
> +		pci_dev->state_saved = false;
> +	}
>  
> -	pci_dev->state_saved = false;
>  	if (pm->suspend) {
>  		pci_power_t prev = pci_dev->current_state;
>  		int error;
> 

  parent reply	other threads:[~2018-05-22 22:01 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-18  8:17 Rafael J. Wysocki
2018-05-18 10:53 ` Mika Westerberg
2018-05-22 22:01 ` Bjorn Helgaas [this message]
2018-05-23  8:11   ` Rafael J. Wysocki

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