From: Keith Busch <kbusch@kernel.org>
To: Mario Limonciello <mario.limonciello@dell.com>
Cc: Crag Wang <Crag.Wang@dell.com>, Sagi Grimberg <sagi@grimberg.me>,
sjg@google.com, LKML <linux-kernel@vger.kernel.org>,
linux-nvme@lists.infradead.org, Jens Axboe <axboe@fb.com>,
Ryan Hong <Ryan.Hong@Dell.com>,
Jared Dominguez <jared.dominguez@dell.com>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH] nvme-pci: Save PCI state before putting drive into deepest state
Date: Tue, 17 Sep 2019 15:24:14 -0600 [thread overview]
Message-ID: <20190917212414.GB39848@C02WT3WMHTD6.wdl.wdc.com> (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:
> The action of saving the PCI state will cause numerous PCI configuration
> space reads which depending upon the vendor implementation may cause
> the drive to exit the deepest NVMe state.
>
> In these cases ASPM will typically resolve the PCIe link state and APST
> may resolve the NVMe power state. However it has also been observed
> that this register access after quiesced will cause PC10 failure
> on some device combinations.
>
> To resolve this, move the PCI state saving to before SetFeatures has been
> called. This has been proven to resolve the issue across a 5000 sample
> test on previously failing disk/system combinations.
>
> Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
> ---
> 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;
> }
> - /*
> - * 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;
In the event that something else fails after the point you've saved
the state, we need to fallback to the behavior for when the driver
doesn't save the state, right?
_______________________________________________
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Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme
next prev parent reply other threads:[~2019-09-17 21:24 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-11 23:42 [PATCH] nvme-pci: Save PCI state before putting drive into deepest state Mario Limonciello
2019-09-17 21:24 ` Keith Busch [this message]
2019-09-17 21:35 ` Rafael J. Wysocki
2019-09-18 16:52 ` Mario.Limonciello
2019-09-18 21:27 ` Rafael J. Wysocki
2019-09-18 17:28 ` Keith Busch
2019-09-18 21:31 ` Rafael J. Wysocki
2019-09-18 21:42 ` Rafael J. Wysocki
2019-09-18 21:43 ` Mario.Limonciello
2019-09-18 21:57 ` Rafael J. Wysocki
2019-09-18 22:00 ` Mario.Limonciello
2019-09-18 22:03 ` Rafael J. Wysocki
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