[PATCH v4 7/7] platform/chrome: cros_ec_typec: Disable tbt on port

From: Abhishek Pandit-Subedi
Date: Fri Dec 06 2024 - 18:40:11 EST


Altmodes with cros_ec are either automatically entered by the EC or
entered by the AP if TBT or USB4 are supported on the system. Due to the
security risk of PCIe tunneling, TBT modes should not be auto entered by
the kernel at this time and will require user intervention.

With this change, a userspace program will need to explicitly activate
the thunderbolt mode on the port and partner in order to enter the mode
and the thunderbolt driver will not automatically enter when a partner
is connected.

Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
---

(no changes since v3)

Changes in v3:
- Set port.inactive = true instead of auto-enter.

Changes in v2:
- Only disable auto-enter for Thunderbolt
- Update commit message to clearly indicate the need for userspace
intervention to enter TBT mode

drivers/platform/chrome/cros_ec_typec.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
index 0b87be52e1db..743cb5a9fe51 100644
--- a/drivers/platform/chrome/cros_ec_typec.c
+++ b/drivers/platform/chrome/cros_ec_typec.c
@@ -311,6 +311,7 @@ static int cros_typec_register_port_altmodes(struct cros_typec_data *typec,
memset(&desc, 0, sizeof(desc));
desc.svid = USB_TYPEC_TBT_SID;
desc.mode = TBT_MODE;
+ desc.inactive = true;
amode = cros_typec_register_thunderbolt(port, &desc);
if (IS_ERR(amode))
return PTR_ERR(amode);
--
2.47.0.338.g60cca15819-goog