From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
We currently disable PTM for Root Ports during suspend. Leaving PTM
enabled for downstream devices causes UR errors if they send PTM Requests.
The intent of this series is to:
- Unconditionally disable PTM during suspend (even if the driver saves
its own state) by moving the disable from pci_prepare_to_sleep() to
pci_pm_suspend().
- Disable PTM for all devices by removing the Root Port condition and
doing it early in the suspend paths.
- Explicitly re-enable PTM during resume.
This got long and pretty complicated to read via the patches. The end
result of ptm.c might help as a roadmap to where I hoped to go:
https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git/tree/drivers/pci/pcie/ptm.c?h=07c2204ab0f3
Basically I wanted to make pci_enable_ptm() and pci_disable_ptm() flip the
PCI_PTM_CTRL_ENABLE bit and nothing else, with all the setup based on the
PTM Capabilities register done in pci_ptm_init().
Bjorn Helgaas (10):
PCI/PTM: Preserve PTM Root Select
PCI/PTM: Cache PTM Capability offset
PCI/PTM: Add pci_upstream_ptm() helper
PCI/PTM: Separate configuration and enable
PCI/PTM: Add pci_disable_ptm() wrapper
PCI/PTM: Add pci_enable_ptm() wrapper
PCI/PTM: Add suspend/resume
PCI/PTM: Move pci_ptm_info() body into its only caller
PCI/PTM: Reorder functions in logical order
PCI/PM: Always disable PTM for all devices during suspend
drivers/pci/pci-driver.c | 11 ++
drivers/pci/pci.c | 28 +---
drivers/pci/pci.h | 6 +-
drivers/pci/pcie/ptm.c | 317 ++++++++++++++++++++-------------------
include/linux/pci.h | 3 +
5 files changed, 181 insertions(+), 184 deletions(-)
--
2.25.1
