USB4 spec says that NFC buffers field is not used for protocol adapters, only for lane adapters so make tb_port_add_nfc_credits() skip non-lane adapters in order to follow the spec. Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> --- drivers/thunderbolt/switch.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c index 698c52775eec..72756c8ceead 100644 --- a/drivers/thunderbolt/switch.c +++ b/drivers/thunderbolt/switch.c @@ -601,6 +601,13 @@ int tb_port_add_nfc_credits(struct tb_port *port, int credits) if (credits == 0 || port->sw->is_unplugged) return 0; + /* + * USB4 restricts programming NFC buffers to lane adapters only + * so skip other ports. + */ + if (tb_switch_is_usb4(port->sw) && !tb_port_is_null(port)) + return 0; + nfc_credits = port->config.nfc_credits & ADP_CS_4_NFC_BUFFERS_MASK; nfc_credits += credits; -- 2.28.0
