Re: [PATCH] nvme-pci: Save PCI state before putting drive into deepest state

From: Keith Busch <kbusch@kernel.org>
To: Mario Limonciello <mario.limonciello@dell.com>
Cc: Jens Axboe <axboe@fb.com>, Christoph Hellwig <hch@lst.de>,
	Sagi Grimberg <sagi@grimberg.me>,
	linux-nvme@lists.infradead.org,
	LKML <linux-kernel@vger.kernel.org>,
	Ryan Hong <Ryan.Hong@Dell.com>, Crag Wang <Crag.Wang@dell.com>,
	sjg@google.com, Jared Dominguez <jared.dominguez@dell.com>
Subject: Re: [PATCH] nvme-pci: Save PCI state before putting drive into deepest state
Date: Wed, 18 Sep 2019 11:28:59 -0600	[thread overview]
Message-ID: <20190918172859.GA51420@C02WT3WMHTD6> (raw)
In-Reply-To: <1568245353-13787-1-git-send-email-mario.limonciello@dell.com>

On Wed, Sep 11, 2019 at 06:42:33PM -0500, Mario Limonciello wrote:
> ---
>  drivers/nvme/host/pci.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 732d5b6..9b3fed4 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -2894,6 +2894,13 @@ static int nvme_suspend(struct device *dev)
>  	if (ret < 0)
>  		goto unfreeze;
>  
> +	/*
> +	 * A saved state prevents pci pm from generically controlling the
> +	 * device's power. If we're using protocol specific settings, we don't
> +	 * want pci interfering.
> +	 */
> +	pci_save_state(pdev);
> +
>  	ret = nvme_set_power_state(ctrl, ctrl->npss);
>  	if (ret < 0)
>  		goto unfreeze;
> @@ -2908,12 +2915,6 @@ static int nvme_suspend(struct device *dev)
>  		ret = 0;
>  		goto unfreeze;

We would need to clear the saved state here, though. You can also
infact remove the unfreeze label and goto.

>  	}
> -	/*
> -	 * A saved state prevents pci pm from generically controlling the
> -	 * device's power. If we're using protocol specific settings, we don't
> -	 * want pci interfering.
> -	 */
> -	pci_save_state(pdev);
>  unfreeze:
>  	nvme_unfreeze(ctrl);
>  	return ret;
> -- 