PCI/PTM: Inherit Switch Downstream Port PTM settings from Upstream Port

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Except for Endpoints, we enable PTM at enumeration-time.  Previously we did
not account for the fact that Switch Downstream Ports are not permitted to
have a PTM capability; their PTM behavior is controlled by the Upstream
Port (PCIe r5.0, sec 7.9.16).  Since Downstream Ports don't have a PTM
capability, we did not mark them as "ptm_enabled", which meant that
pci_enable_ptm() on an Endpoint failed because there was no PTM path to it.

Mark Downstream Ports as "ptm_enabled" if their Upstream Port has PTM
enabled.

Fixes: eec097d431 ("PCI: Add pci_enable_ptm() for drivers to enable PTM on endpoints")
Reported-by: Aditya Paluri <Venkata.AdityaPaluri@synopsys.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

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This commit is contained in:

Bjorn Helgaas 2020-05-21 15:40:07 -05:00

parent aa0ce96d72

commit 7b38fd9760

1 changed files with 17 additions and 5 deletions

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drivers/pci/pcie/ptm.c

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