[PATCH 0/1][SRU][F/OEM-5.6/G] UBUNTU: SAUCE: Fix disk probing under SATA controller behind VMD

[You-Sheng Yang]

BugLink: https://bugs.launchpad.net/bugs/1894778

[Impact]

When booting with a certain platforms with boot disk attached to SATA
bus behind Intel VMD controller, disk probing may fail with following
error messages left in dmesg:

  [ 6.163286] ata1.00: qc timeout (cmd 0xec)
  [ 6.165630] ata1.00: failed to IDENTIFY (I/O error, err_mask=0x4)

[Fix]

Proposed kernel patch https://patchwork.kernel.org/patch/11758345/

[Test Case]

Check dmesg/lsblk for disk probe.

For pci MSI address, check lspci output:

  $ lspci -vvnn
  ....
      Capabilities: [80] MSI: Enable+ Count=1/1 maskable- 64bit-
          Address: fee00000  Data: 0000

When it fails, the address is fee00000. And with a patched kernel:

  $ lspci -vvnn
  ....
      Capabilities: [80] MSI: Enable+ Count=1/1 maskable- 64bit-
          Address: fee01000  Data: 0000

[Regression Potential]
Low.  For previous NVMe based platforms, this patch brings no effective
change for NVMe devices because they will still stay in fast-interrupt
list.

Jon Derrick (1):
  PCI: vmd: Add AHCI to fast interrupt list

 drivers/pci/controller/vmd.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

-- 
2.27.0