From: Keith Busch <kbusch@kernel.org>
Date: Mon, 6 Jun 2022 09:53:17 -0700
Subject: nvme-pci: add trouble shooting steps for timeouts
Patch-mainline: v5.19-rc3
Git-commit: 4641a8e6e145f595059e695f0f8dbbe608134086
References: jsc#PED-1183

Many users have encountered IO timeouts with a CSTS value of 0xffffffff,
which indicates a failure to read the register. While there are various
potential causes for this observation, faulty NVMe APST has been the
culprit quite frequently. Add the recommended troubleshooting steps in
the error output when this condition occurs.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Daniel Wagner <dwagner@suse.de>
---
 drivers/nvme/host/pci.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1334,6 +1334,14 @@ static void nvme_warn_reset(struct nvme_
 		dev_warn(dev->ctrl.device,
 			 "controller is down; will reset: CSTS=0x%x, PCI_STATUS read failed (%d)\n",
 			 csts, result);
+
+	if (csts != ~0)
+		return;
+
+	dev_warn(dev->ctrl.device,
+		 "Does your device have a faulty power saving mode enabled?\n");
+	dev_warn(dev->ctrl.device,
+		 "Try \"nvme_core.default_ps_max_latency_us=0 pcie_aspm=off\" and report a bug\n");
 }
 
 static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved)