On 12/9/22 9:07 AM, Bjorn Helgaas wrote: > On Wed, Dec 07, 2022 at 10:41:05AM +0200, Mika Westerberg wrote: >> Only Root Ports and Event Collectors use MSI for AER. PCIe Switch ports >> or endpoints on the other hand only send messages (that get collected by >> the former). For this reason do not require PCIe switch ports and >> endpoints to use interrupt if they support AER. >> >> This allows portdrv to attach PCIe switch ports of Intel DG1 and DG2 >> discrete graphics cards. These do not declare MSI or legacy interrupts. >> >> Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> > > Thanks for the additional info! This seems like something we should > definitely do. > > I'm wondering whether we should check for this in > get_port_device_capability(). It already has similar checks for > device type for other services. This would skip pci_set_master() for > these non-RP, non-RCEC devices, which is probably harmless, since I > assume we only need that to make sure MSI works. Currently, we only have high level (cap or enable/disable) checks in get_port_device_capability(). Why bring in more AER specific checks there and make it complicated? Is there any benefit in doing this? > > It would also prevent allocation of the AER service for non-RP, > non-RCEC devices. That's also probably harmless, since aer_probe() > ignores those devices anyway. > > What do you think of something like this? (This is based on my > pci/portdrv branch which squashed everything into portdrv.c: > https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git/log/?h=pci/portdrv) > > diff --git a/drivers/pci/pcie/portdrv.c b/drivers/pci/pcie/portdrv.c > index a6c4225505d5..8b16e96ec15c 100644 > --- a/drivers/pci/pcie/portdrv.c > +++ b/drivers/pci/pcie/portdrv.c > @@ -232,7 +232,9 @@ static int get_port_device_capability(struct pci_dev *dev) > } > > #ifdef CONFIG_PCIEAER > - if (dev->aer_cap && pci_aer_available() && > + if ((pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT || > + pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC) && > + dev->aer_cap && pci_aer_available() && > (pcie_ports_native || host->native_aer)) > services |= PCIE_PORT_SERVICE_AER; > #endif If you want to do it, will you remove the relevant check in AER driver probe? -- Sathyanarayanan Kuppuswamy Linux Kernel Developer
