From: Christoph Hellwig <hch@lst.de>
Date: Wed, 3 Jun 2020 08:24:17 +0200
Subject: [PATCH] nvme-pci: use simple suspend when a HMB is enabled
Git-commit: b97120b15ebd3de51325084136d3b9c3cce656d6
Patch-mainline: v5.8-rc1
References: git-fixes
While the NVMe specification allows the device to access the host memory
buffer in host DRAM from all power states, hosts will fail access to
DRAM during S3 and similar power states.
Fixes: d916b1be94b6 ("nvme-pci: use host managed power state for suspend")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
drivers/nvme/host/pci.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index d690d5593a80..e2bacd369a88 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2950,9 +2950,15 @@ static int nvme_suspend(struct device *dev)
* the PCI bus layer to put it into D3 in order to take the PCIe link
* down, so as to allow the platform to achieve its minimum low-power
* state (which may not be possible if the link is up).
+ *
+ * If a host memory buffer is enabled, shut down the device as the NVMe
+ * specification allows the device to access the host memory buffer in
+ * host DRAM from all power states, but hosts will fail access to DRAM
+ * during S3.
*/
if (pm_suspend_via_firmware() || !ctrl->npss ||
!pcie_aspm_enabled(pdev) ||
+ ndev->nr_host_mem_descs ||
(ndev->ctrl.quirks & NVME_QUIRK_SIMPLE_SUSPEND))
return nvme_disable_prepare_reset(ndev, true);
--
2.29.2