diff --git a/drivers/thunderbolt/usb4.c b/drivers/thunderbolt/usb4.c index 90986567f1f9..8c61fe78f7fb 100644 --- a/drivers/thunderbolt/usb4.c +++ b/drivers/thunderbolt/usb4.c @@ -1930,18 +1930,30 @@ static int usb4_usb3_port_write_allocated_bandwidth(struct tb_port *port, int downstream_bw) { u32 val, ubw, dbw, scale; - int ret; + int ret, max_bw; - /* Read the used scale, hardware default is 0 */ - ret = tb_port_read(port, &scale, TB_CFG_PORT, - port->cap_adap + ADP_USB3_CS_3, 1); + /* Figure out suitable scale */ + scale = 0; + max_bw = max(upstream_bw, downstream_bw); + while (scale < 64) { + if (mbps_to_usb3_bw(max_bw, scale) < 4096) + break; + scale++; + } + + if (WARN_ON(scale >= 64)) + return -EINVAL; + + ret = tb_port_write(port, &scale, TB_CFG_PORT, + port->cap_adap + ADP_USB3_CS_3, 1); if (ret) return ret; - scale &= ADP_USB3_CS_3_SCALE_MASK; ubw = mbps_to_usb3_bw(upstream_bw, scale); dbw = mbps_to_usb3_bw(downstream_bw, scale); + tb_port_dbg(port, "scaled bandwidth %u/%u, scale %u\n", ubw, dbw, scale); + ret = tb_port_read(port, &val, TB_CFG_PORT, port->cap_adap + ADP_USB3_CS_2, 1); if (ret)