From 25d905d2b81973426b73ad943342dfda4e9a6fb5 Mon Sep 17 00:00:00 2001 From: Gil Fine Date: Mon, 12 Feb 2024 00:33:24 +0200 Subject: thunderbolt: Allow USB3 bandwidth to be lower than maximum supported Currently USB3 tunnel setup fails if USB4 link available bandwidth is too low to allow USB3 Maximum Supported Link Rate. In reality, this limitation is not needed, and may cause failure of USB3 tunnel establishment, if USB4 link available bandwidth is lower than USB3 Maximum Supported Link Rate. E.g. if we connect to USB4 v1 host router, a USB4 v1 device router, via 10 Gb/s cable. Hence, here we discard this limitation, and now we only limit USB3 bandwidth allocation to be not higher than 90% of USB3 Max Supported Link Rate (for first USB3 tunnel only). Signed-off-by: Gil Fine Signed-off-by: Mika Westerberg --- drivers/thunderbolt/tunnel.c | 25 ++++++++++--------------- 1 file changed, 10 insertions(+), 15 deletions(-) diff --git a/drivers/thunderbolt/tunnel.c b/drivers/thunderbolt/tunnel.c index cb6609a56a03..fdc5e8e12ca8 100644 --- a/drivers/thunderbolt/tunnel.c +++ b/drivers/thunderbolt/tunnel.c @@ -2064,26 +2064,21 @@ struct tb_tunnel *tb_tunnel_alloc_usb3(struct tb *tb, struct tb_port *up, { struct tb_tunnel *tunnel; struct tb_path *path; - int max_rate = 0; + int max_rate; - /* - * Check that we have enough bandwidth available for the new - * USB3 tunnel. - */ - if (max_up > 0 || max_down > 0) { + if (!tb_route(down->sw) && (max_up > 0 || max_down > 0)) { + /* + * For USB3 isochronous transfers, we allow bandwidth which is + * not higher than 90% of maximum supported bandwidth by USB3 + * adapters. + */ max_rate = tb_usb3_max_link_rate(down, up); if (max_rate < 0) return NULL; - /* Only 90% can be allocated for USB3 isochronous transfers */ max_rate = max_rate * 90 / 100; - tb_port_dbg(up, "required bandwidth for USB3 tunnel %d Mb/s\n", + tb_port_dbg(up, "maximum required bandwidth for USB3 tunnel %d Mb/s\n", max_rate); - - if (max_rate > max_up || max_rate > max_down) { - tb_port_warn(up, "not enough bandwidth for USB3 tunnel\n"); - return NULL; - } } tunnel = tb_tunnel_alloc(tb, 2, TB_TUNNEL_USB3); @@ -2115,8 +2110,8 @@ struct tb_tunnel *tb_tunnel_alloc_usb3(struct tb *tb, struct tb_port *up, tunnel->paths[TB_USB3_PATH_UP] = path; if (!tb_route(down->sw)) { - tunnel->allocated_up = max_rate; - tunnel->allocated_down = max_rate; + tunnel->allocated_up = min(max_rate, max_up); + tunnel->allocated_down = min(max_rate, max_down); tunnel->init = tb_usb3_init; tunnel->consumed_bandwidth = tb_usb3_consumed_bandwidth; -- cgit v1.2.3