[PATCH 6.18 244/277] usb: typec: thunderbolt: Set enter_vdo during initialization

Greg Kroah-Hartman
2026-04-08T18:37:52Z

From: Andrei Kuchynski <akuchynski@chromium.org>

commit 3b8ae9817686efb3ea789ca9d4efdff2ce9c1c04 upstream.

In the current implementation, if a cable's alternate mode enter operation
is not supported, the tbt->plug[TYPEC_PLUG_SOP_P] pointer is cleared by the
time tbt_enter_mode() is called. This prevents the driver from identifying
the cable's VDO.

As a result, the Thunderbolt connection falls back to the default
TBT_CABLE_USB3_PASSIVE speed, even if the cable supports higher speeds.
To ensure the correct VDO value is used during mode entry, calculate and
store the enter_vdo earlier during the initialization phase in tbt_ready().

Cc: stable <stable@kernel.org>
Fixes: 100e25738659 ("usb: typec: Add driver for Thunderbolt 3 Alternate Mode")
Tested-by: Madhu M <madhu.m@intel.corp-partner.google.com>
Signed-off-by: Andrei Kuchynski <akuchynski@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Benson Leung <bleung@chromium.org>
Link: https://patch.msgid.link/20260324103012.1417616-1-akuchynski@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/typec/altmodes/thunderbolt.c | 44 +++++++++++++++----------------
1 file changed, 22 insertions(+), 22 deletions(-)

--- a/drivers/usb/typec/altmodes/thunderbolt.c
+++ b/drivers/usb/typec/altmodes/thunderbolt.c
@@ -39,28 +39,7 @@ static bool tbt_ready(struct typec_altmo

static int tbt_enter_mode(struct tbt_altmode *tbt)
{
- struct typec_altmode *plug = tbt->plug[TYPEC_PLUG_SOP_P];
- u32 vdo;
-
- vdo = tbt->alt->vdo & (TBT_VENDOR_SPECIFIC_B0 | TBT_VENDOR_SPECIFIC_B1);
- vdo |= tbt->alt->vdo & TBT_INTEL_SPECIFIC_B0;
- vdo |= TBT_MODE;
-
- if (plug) {
- if (typec_cable_is_active(tbt->cable))
- vdo |= TBT_ENTER_MODE_ACTIVE_CABLE;
-
- vdo |= TBT_ENTER_MODE_CABLE_SPEED(TBT_CABLE_SPEED(plug->vdo));
- vdo |= plug->vdo & TBT_CABLE_ROUNDED;
- vdo |= plug->vdo & TBT_CABLE_OPTICAL;
- vdo |= plug->vdo & TBT_CABLE_RETIMER;
- vdo |= plug->vdo & TBT_CABLE_LINK_TRAINING;
- } else {
- vdo |= TBT_ENTER_MODE_CABLE_SPEED(TBT_CABLE_USB3_PASSIVE);
- }
-
- tbt->enter_vdo = vdo;
- return typec_altmode_enter(tbt->alt, &vdo);
+ return typec_altmode_enter(tbt->alt, &tbt->enter_vdo);
}

static void tbt_altmode_work(struct work_struct *work)
@@ -337,6 +316,7 @@ static bool tbt_ready(struct typec_altmo
{
struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
struct typec_altmode *plug;
+ u32 vdo;

if (tbt->cable)
return true;
@@ -364,6 +344,26 @@ static bool tbt_ready(struct typec_altmo
tbt->plug[i] = plug;
}

+ vdo = tbt->alt->vdo & (TBT_VENDOR_SPECIFIC_B0 | TBT_VENDOR_SPECIFIC_B1);
+ vdo |= tbt->alt->vdo & TBT_INTEL_SPECIFIC_B0;
+ vdo |= TBT_MODE;
+ plug = tbt->plug[TYPEC_PLUG_SOP_P];
+
+ if (plug) {
+ if (typec_cable_is_active(tbt->cable))
+ vdo |= TBT_ENTER_MODE_ACTIVE_CABLE;
+
+ vdo |= TBT_ENTER_MODE_CABLE_SPEED(TBT_CABLE_SPEED(plug->vdo));
+ vdo |= plug->vdo & TBT_CABLE_ROUNDED;
+ vdo |= plug->vdo & TBT_CABLE_OPTICAL;
+ vdo |= plug->vdo & TBT_CABLE_RETIMER;
+ vdo |= plug->vdo & TBT_CABLE_LINK_TRAINING;
+ } else {
+ vdo |= TBT_ENTER_MODE_CABLE_SPEED(TBT_CABLE_USB3_PASSIVE);
+ }
+
+ tbt->enter_vdo = vdo;
+
return true;
}