[PATCH v2 0/3] PCI: Add PCI_ERROR_RESPONSE, check for errors

[Bjorn Helgaas <helgaas@kernel.org>]

From: Bjorn Helgaas <bhelgaas@google.com>

Reads from a PCI device may fail if the device has been turned off (put
into D3cold), removed, or if some other error occurs.  The PCI host bridge
typically fabricates ~0 data to complete the CPU's read.

We check for that in a few places, but not in a consistent way.  This
series adds a PCI_ERROR_RESPONSE definition to make the checks more
consistent and easier to find.  Note that ~0 may indicate a PCI error, but
it may also be valid read data, so you need more information (such as
knowing that a register can never contain ~0) before concluding that it's
an error.

This series also adds a new check for PCI_ERROR_RESPONSE in the power
management code because that code frequently encounters devices in D3cold,
where we previously misinterpreted ~0 data.  It also uses pci_power_name()
to print D-state names more consistently.

Rafael, I didn't add your Reviewed-by to "PCI / PM: Return error when
changing power state from D3cold" because I made small changes to try to
make the messages more consistent, and I didn't want to presume they'd be
OK with you.

Changes since v1:
  - Add Rafael's Reviewed-By to the first two patches
  - Drop "PCI / PM: Check for error when reading PME status" because Rafael
    pointed out that some devices can signal PME even when in D3cold, so
    this would require additional rework
  - Drop "PCI / PM: Check for error when reading Power State" because
    Rafael thinks it's mostly redundant

Bjorn Helgaas (3):
  PCI: Add PCI_ERROR_RESPONSE definition
  PCI / PM: Decode D3cold power state correctly
  PCI / PM: Return error when changing power state from D3cold

 drivers/pci/access.c                          | 13 ++++----
 .../pci/controller/dwc/pcie-designware-host.c |  2 +-
 drivers/pci/controller/pci-aardvark.c         |  2 +-
 drivers/pci/controller/pci-mvebu.c            |  4 +--
 drivers/pci/controller/pci-thunder-ecam.c     | 20 ++++++------
 drivers/pci/controller/pci-thunder-pem.c      |  2 +-
 drivers/pci/controller/pcie-altera.c          |  2 +-
 drivers/pci/controller/pcie-iproc.c           |  2 +-
 drivers/pci/controller/pcie-mediatek.c        |  4 +--
 drivers/pci/controller/pcie-rcar.c            |  2 +-
 drivers/pci/controller/pcie-rockchip-host.c   |  2 +-
 drivers/pci/controller/vmd.c                  |  2 +-
 drivers/pci/hotplug/cpqphp_ctrl.c             | 12 +++----
 drivers/pci/hotplug/cpqphp_pci.c              | 20 ++++++------
 drivers/pci/hotplug/pciehp_hpc.c              |  6 ++--
 drivers/pci/pci.c                             | 31 ++++++++++++-------
 drivers/pci/pcie/dpc.c                        |  3 +-
 drivers/pci/pcie/pme.c                        |  4 +--
 drivers/pci/probe.c                           |  4 +--
 drivers/pci/quirks.c                          |  2 +-
 include/linux/pci.h                           |  7 +++++
 21 files changed, 81 insertions(+), 65 deletions(-)

-- 
2.23.0.187.g17f5b7556c-goog