[PATCH v3] PCI/portdrv: Allow AER service only for Root Ports & RCECs

[Matthew W Carlis <mattc@purestorage.com>]

Hello Any Interested

Recently found that this patch had the affect of requiring us to set
pcie_ports_dpc_native in order to use the kernel DPC driver with PCIe switch
downstream ports. The kernel check for the DPC capability in portdrv.c has;
if pci_aer_available() and (dpc-native or using AER port service driver on
the device). I wonder if we couldn't do away with the requirement of the
AER service being used on the port if pci_aer_available() & host->native_aer
don't lie. I'm still trying to decide exactly what the condition ought to
look like, but it might draw from the AER service check above it. For example:

        if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
-           pci_aer_available() &&
-           (pcie_ports_dpc_native || (services & PCIE_PORT_SERVICE_AER)))
+           dev->aer_cap && pci_aer_available() &&
+           (pcie_ports_dpc_native || host->native_aer))
                services |= PCIE_PORT_SERVICE_DPC;

Thanks,
-Matt