[PATCH v9 0/2] PCI: Disable AER & DPC on suspend

[Bjorn Helgaas]

From: Bjorn Helgaas <bhelgaas at google.com>

This is an old series from Kai-Heng that I didn't handle soon enough.  The
intent is to fix several suspend/resume issues:

  - Spurious wakeup from s2idle
    (https://bugzilla.kernel.org/show_bug.cgi?id=216295)

  - Steam Deck doesn't resume after suspend
    (https://bugzilla.kernel.org/show_bug.cgi?id=218090)

  - Unexpected ACS error and DPC event when resuming after suspend
    (https://bugzilla.kernel.org/show_bug.cgi?id=209149)

It seems that a glitch when the link is powered down during suspend causes
errors to be logged by AER.  When AER is enabled, this causes an AER
interrupt, and if that IRQ is shared with PME, it may cause a spurious
wakeup.

Also, errors logged during link power-down and power-up seem to cause
unwanted error reporting during resume.

This series disables AER interrupts, DPC triggering, and DPC interrupts
during suspend.  On resume, it clears AER and DPC error status before
re-enabling their interrupts.

I added a couple cosmetic changes for the v9, but this is essentially all
Kai-Heng's work.  I'm just posting it as a v9 because I failed to act on
this earlier.

Bjorn

v9:
 - Drop pci_ancestor_pr3_present() and pm_suspend_via_firmware; do it
   unconditionally
 - Clear DPC status before re-enabling DPC interrupt

v8: https://lore.kernel.org/r/20240416043225.1462548-1-kai.heng.feng@canonical.com
 - Wording.
 - Add more bug reports.

v7:
 - Wording.
 - Disable AER completely (again) if power will be turned off
 - Disable DPC completely (again) if power will be turned off

v6: https://lore.kernel.org/r/20230512000014.118942-1-kai.heng.feng@canonical.com

v5: https://lore.kernel.org/r/20230511133610.99759-1-kai.heng.feng@canonical.com
 - Wording.

v4: https://lore.kernel.org/r/20230424055249.460381-1-kai.heng.feng@canonical.com
v3: https://lore.kernel.org/r/20230420125941.333675-1-kai.heng.feng@canonical.com
 - Correct subject.

v2: https://lore.kernel.org/r/20230420015830.309845-1-kai.heng.feng@canonical.com
 - Only disable AER IRQ.
 - No more AER check on PME IRQ#.
 - Use AER helper.
 - Only disable DPC IRQ.
 - No more DPC check on PME IRQ#.

v1: https://lore.kernel.org/r/20220727013255.269815-1-kai.heng.feng@canonical.com

Kai-Heng Feng (2):
  PCI/AER: Disable AER service on suspend
  PCI/DPC: Disable DPC service on suspend

 drivers/pci/pcie/aer.c | 18 +++++++++++++
 drivers/pci/pcie/dpc.c | 60 +++++++++++++++++++++++++++++++++---------
 2 files changed, 66 insertions(+), 12 deletions(-)

-- 
2.34.1