Merge tag 'thunderbolt-for-v6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/westeri/thunderbolt into char-misc-next

Mika writes:

thunderbolt: Changes for v6.8 merge window

This includes following USB4/Thunderbolt changes for the v6.8 merge
window:

  - Intel Lunar Lake support
  - PCIe tunneling improvements
  - DisplayPort tunneling improvements
  - Asymmetric switching improvements
  - Couple of minor fixes and cleanups.

All these have been in linux-next with no reported issues.

* tag 'thunderbolt-for-v6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/westeri/thunderbolt:
  thunderbolt: Reduce retry timeout to speed up boot for some devices
  thunderbolt: Keep link as asymmetric if preferred by hardware
  thunderbolt: Add support for Intel Lunar Lake
  thunderbolt: Disable PCIe extended encapsulation upon teardown properly
  thunderbolt: Make PCIe tunnel setup and teardown follow CM guide
  thunderbolt: Improve logging when DisplayPort resource is added due to hotplug
  thunderbolt: Use tb_dp_read_cap() to read DP_COMMON_CAP as well
  thunderbolt: Disable CL states only when actually needed
  thunderbolt: Transition link to asymmetric only when both sides support it
  thunderbolt: Log XDomain link speed and width
  thunderbolt: Move width_name() helper to tb.h
  thunderbolt: Handle lane bonding of Gen 4 XDomain links properly
  thunderbolt: Unwind TMU configuration if tb_switch_set_tmu_mode_params() fails
  thunderbolt: Remove duplicated re-assignment of pointer 'out'

1 files changed, 15 insertions, 18 deletions

diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index 44e9b09de47a..900114ba4371 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -941,22 +941,6 @@ int tb_port_get_link_generation(struct tb_port *port)
 	}
 }
 
-static const char *width_name(enum tb_link_width width)
-{
-	switch (width) {
-	case TB_LINK_WIDTH_SINGLE:
-		return "symmetric, single lane";
-	case TB_LINK_WIDTH_DUAL:
-		return "symmetric, dual lanes";
-	case TB_LINK_WIDTH_ASYM_TX:
-		return "asymmetric, 3 transmitters, 1 receiver";
-	case TB_LINK_WIDTH_ASYM_RX:
-		return "asymmetric, 3 receivers, 1 transmitter";
-	default:
-		return "unknown";
-	}
-}
-
 /**
  * tb_port_get_link_width() - Get current link width
  * @port: Port to check (USB4 or CIO)
@@ -2769,7 +2753,7 @@ static void tb_switch_link_init(struct tb_switch *sw)
 		return;
 
 	tb_sw_dbg(sw, "current link speed %u.0 Gb/s\n", sw->link_speed);
-	tb_sw_dbg(sw, "current link width %s\n", width_name(sw->link_width));
+	tb_sw_dbg(sw, "current link width %s\n", tb_width_name(sw->link_width));
 
 	bonded = sw->link_width >= TB_LINK_WIDTH_DUAL;
 
@@ -2789,6 +2773,19 @@ static void tb_switch_link_init(struct tb_switch *sw)
 	if (down->dual_link_port)
 		down->dual_link_port->bonded = bonded;
 	tb_port_update_credits(down);
+
+	if (tb_port_get_link_generation(up) < 4)
+		return;
+
+	/*
+	 * Set the Gen 4 preferred link width. This is what the router
+	 * prefers when the link is brought up. If the router does not
+	 * support asymmetric link configuration, this also will be set
+	 * to TB_LINK_WIDTH_DUAL.
+	 */
+	sw->preferred_link_width = sw->link_width;
+	tb_sw_dbg(sw, "preferred link width %s\n",
+		  tb_width_name(sw->preferred_link_width));
 }
 
 /**
@@ -3029,7 +3026,7 @@ int tb_switch_set_link_width(struct tb_switch *sw, enum tb_link_width width)
 
 	tb_switch_update_link_attributes(sw);
 
-	tb_sw_dbg(sw, "link width set to %s\n", width_name(width));
+	tb_sw_dbg(sw, "link width set to %s\n", tb_width_name(width));
 	return ret;
 }