On Wed, Feb 06, 2019 at 04:17:26PM +0300, Mika Westerberg wrote: > /* dword 0 */ > hop.next_hop = path->hops[i].next_hop_index; > hop.out_port = path->hops[i].out_port->port; > - /* TODO: figure out why these are good values */ > - hop.initial_credits = (i == path->path_length - 1) ? 16 : 7; > + hop.initial_credits = path->hops[i].initial_credits; > hop.unknown1 = 0; > hop.enable = 1; [...] > @@ -78,6 +78,74 @@ static void tb_pci_init_path(struct tb_path *path) > path->weight = 1; > path->drop_packages = 0; > path->nfc_credits = 0; > + path->hops[0].initial_credits = 7; > + path->hops[1].initial_credits = 16;
I guess Andreas' algorithm (the last hop in the path is assigned 16 and all the ones before are assigned 7) was reverse-engineered from Apple's driver. The fact that this algorithm works for paths of arbitrary length could indicate that Apple indeed does establish tunnels between non-adjacent switches. Also, why are these good values? (You've deleted the comment.) Thanks, Lukas
