[PATCH v2 5/7] thunderbolt: increase the lane adapter link-up timeout value

[Chunfeng Yun]

when plug into a USB3 device into USB4 hub's downstream facing port
to trigger usb4 driver wakeup, encounter the lane link up timeout
issue, then cause usb3 hub disconnect:

usb4_hi NVDA8100:00: 0:1: failed to reach state TB_PORT_UP. Ignoring port...
usb4_hi NVDA8100:00: 0:1: lost during suspend, disconnecting
usb4_hi NVDA8100:00: 0:4 <-> 1:20 (USB3): deactivating
usb4_hi NVDA8100:00: deactivating USB3 Down path from 0:4 to 1:20
usb4_hi NVDA8100:00: deactivating USB3 Up path from 1:20 to 0:4
...
thunderbolt 0-1: device disconnected
usb 2-1: USB disconnect, device number 10

Completes link training at ~1.48s (with two retimer) and transitions
to TB_PORT_UP after change the timeout to 2s;

In the USB4 spec, Phase 5 (Link Equalization) alone is allowed up to
1000 ms. When add tPhase2~4 (200 ms), and retimer transaction delays
(tCmdResponse = 50 ms), the physical link is allowed by spec to take
1200 ms to 1500 ms+ to complete initialization.

Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
---
v2: change timeout from 2.5s to 2s
---
 drivers/thunderbolt/switch.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index 7ff3da79da76..7daee83c7ed8 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -486,7 +486,7 @@ int tb_port_state(struct tb_port *port)
  * @port: Port to wait
  * @wait_if_unplugged: Wait also when port is unplugged
  *
- * Wait up to 1 second for a port to reach state TB_PORT_UP. If
+ * Wait up to 2 seconds for a port to reach state TB_PORT_UP. If
  * wait_if_unplugged is set then we also wait if the port is in state
  * TB_PORT_UNPLUGGED (it takes a while for the device to be registered after
  * switch resume). Otherwise we only wait if a device is registered but the link
@@ -500,7 +500,7 @@ int tb_port_state(struct tb_port *port)
  */
 int tb_wait_for_port(struct tb_port *port, bool wait_if_unplugged)
 {
-	int retries = 10;
+	int retries = 20;
 	int state;
 	if (!port->cap_phy) {
 		tb_port_WARN(port, "does not have PHY\n");
-- 
2.45.2