On Fri, Apr 30, 2021 at 2:43 PM Shujun Wang [off-list ref] wrote:

This reverts commit 7e4fdeafa61f2b653fcf9678f09935e55756aed2.
It may cause some NVMe device probes to fail, and the system may get
stuck when using an NVMe device as the root filesystem.

In the function nvme_pci_enable(struct nvme_dev *dev), as shown below,
readl(NVME_REG_CSTS) always returns -1 with the commit, which results in
the probe failed.

  if (readl(dev->bar + NVME_REG_CSTS) == -1) {
        result = -ENODEV;
        goto disable;
  }

dmesg:
  [    1.106280] nvme 0000:04:00.0: platform quirk: setting simple suspend
  [    1.109111] nvme nvme0: pci function 0000:04:00.0
  [    1.113066] nvme 0000:04:00.0: enabling device (0000 -> 0002)
  [    1.121040] nvme nvme0: Removing after probe failure status: -19

lspci:
  Non-Volatile memory controller: KIOXIA Corporation Device 0001

device uevent:
  DRIVER=nvme
  PCI_CLASS=10802
  PCI_ID=1E0F:0001
  PCI_SUBSYS_ID=1E0F:0001
  PCI_SLOT_NAME=0000:04:00.0
  MODALIAS=pci:v00001E0Fd00000001sv00001E0Fsd00000001bc01sc08i02

This patch was tested in Lenovo Thinkpad X1.

Please send me the dmidecode output from this machine or (better)
attach it at https://bugzilla.kernel.org/show_bug.cgi?id=213019

Thanks!