Hi Jon, I'm glad you raised this because I think the way we handle FIRMWARE_FIRST is really screwed up.
On Mon, Apr 20, 2020 at 03:37:09PM -0600, Jon Derrick wrote: > Some platforms have a mix of ports whose capabilities can be negotiated > by _OSC, and some ports which are not described by ACPI and instead > managed by Native drivers. The existing Firmware-First HEST model can > incorrectly tag these Native, Non-ACPI ports as Firmware-First managed > ports by advertising the HEST Global Flag and matching the type and > class of the port (aer_hest_parse). > > If the port requests Native AER through the Host Bridge's capability > settings, the AER driver should honor those settings and allow the port > to bind. This patch changes the definition of Firmware-First to exclude > ports whose Host Bridges request Native AER. > > Signed-off-by: Jon Derrick <jonathan.derr...@intel.com> > --- > drivers/pci/pcie/aer.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c > index f4274d3..30fbd1f 100644 > --- a/drivers/pci/pcie/aer.c > +++ b/drivers/pci/pcie/aer.c > @@ -314,6 +314,9 @@ int pcie_aer_get_firmware_first(struct pci_dev *dev) > if (pcie_ports_native) > return 0; > > + if (pci_find_host_bridge(dev->bus)->native_aer) > + return 0; I hope we don't have to complicate pcie_aer_get_firmware_first() by adding this "native_aer" check here. I'm not sure what we actually *should* do based on FIRMWARE_FIRST, but I don't think the current uses really make sense. I think Linux makes too many assumptions based on the FIRMWARE_FIRST bit. The ACPI spec really only says (ACPI v6.3, sec 18.3.2.4): If set, FIRMWARE_FIRST indicates to the OSPM that system firmware will handle errors from this source first. If FIRMWARE_FIRST is set in the flags field, the Enabled field [of the HEST AER structure] is ignored by the OSPM. I do not see anything there about who owns the AER Capability, but Linux assumes that if FIRMWARE_FIRST is set, firmware must own the AER Capability. I think that's reading too much into the spec. We already have _OSC, which *does* explicitly talk about who owns the AER Capability, and I think we should rely on that. If firmware doesn't want the OS to touch the AER Capability, it should decline to give ownership to the OS via _OSC. > if (!dev->__aer_firmware_first_valid) > aer_set_firmware_first(dev); > return dev->__aer_firmware_first; > -- > 1.8.3.1 >
