On Wed, May 28, 2025 at 05:35:00PM -0500, Bjorn Helgaas wrote: > On Thu, May 08, 2025 at 12:40:33PM +0530, Manivannan Sadhasivam wrote: > > The PCI link, when down, needs to be recovered to bring it back. But that > > cannot be done in a generic way as link recovery procedure is specific to > > host bridges. So add a new API pci_host_handle_link_down() that could be > > called by the host bridge drivers when the link goes down. > > > > The API will iterate through all the slots and calls the pcie_do_recovery() > > function with 'pci_channel_io_frozen' as the state. This will result in the > > execution of the AER Fatal error handling code. Since the link down > > recovery is pretty much the same as AER Fatal error handling, > > pcie_do_recovery() helper is reused here. First the AER error_detected > > callback will be triggered for the bridge and the downstream devices. Then, > > pci_host_reset_slot() will be called for the slot, which will reset the > > slot using 'reset_slot' callback to recover the link. Once that's done, > > resume message will be broadcasted to the bridge and the downstream devices > > indicating successful link recovery. > > Link down is an event for a single Root Port. Why would we iterate > through all the Root Ports if the link went down for one of them?
Because on the reference platform (Qcom), link down notification is not per-port, but per controller. So that's why we are iterating through all ports. The callback is supposed to identify the ports that triggered the link down event and recover them. - Mani -- மணிவண்ணன் சதாசிவம்
