linux-kernel - [PATCH] nvme-pci: Shutdown the device if D3Cold is allowed by the user

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Message-Id: <20241118082344.8146-1-manivannan.sadhasivam@linaro.org>
Date: Mon, 18 Nov 2024 13:53:44 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: kbusch@...nel.org,
	axboe@...nel.dk,
	hch@....de,
	sagi@...mberg.me
Cc: linux-nvme@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	linux-pci@...r.kernel.org,
	andersson@...nel.org,
	konradybcio@...nel.org,
	Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
Subject: [PATCH] nvme-pci: Shutdown the device if D3Cold is allowed by the user

PCI core allows users to configure the D3Cold state for each PCI device
through the sysfs attribute '/sys/bus/pci/devices/.../d3cold_allowed'. This
attribute sets the 'pci_dev:d3cold_allowed' flag and could be used by users
to allow/disallow the PCI devices to enter D3Cold during system suspend.

So make use of this flag in the NVMe driver to shutdown the NVMe device
during system suspend if the user has allowed D3Cold for the device.
Existing checks in the NVMe driver decide whether to shut down the device
(based on platform/device limitations), so use this flag as the last resort
to keep the existing behavior.

The default behavior of the 'pci_dev:d3cold_allowed' flag is to allow
D3Cold and the users can disallow it through sysfs if they want.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
---
 drivers/nvme/host/pci.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 4b9fda0b1d9a..a4d4687854bf 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -3287,7 +3287,8 @@ static int nvme_suspend(struct device *dev)
 	 */
 	if (pm_suspend_via_firmware() || !ctrl->npss ||
 	    !pcie_aspm_enabled(pdev) ||
-	    (ndev->ctrl.quirks & NVME_QUIRK_SIMPLE_SUSPEND))
+	    (ndev->ctrl.quirks & NVME_QUIRK_SIMPLE_SUSPEND) ||
+	    pdev->d3cold_allowed)
 		return nvme_disable_prepare_reset(ndev, true);

 	nvme_start_freeze(ctrl);
-- 
2.25.1