From: Stanisław Titenko The Lenovo ThinkPad T14 Gen 2a exposes a functional UCSI ACPI PPM but the firmware leaves the VERSION field of the UCSI mailbox at zero. ucsi_register() rejects a zero version with -ENODEV, leaving the system without registered USB Type-C connectors. Without an OPM, the embedded controller does not complete DisplayPort Alternate Mode setup when a USB-C dock or monitor that supplies power is connected after boot, so the display stays dark while USB and charging work. Use the zero version quirk for the ThinkPad T14 Gen 2a, matching the two board names of this model (20XK and 20XL). Tested on a ThinkPad T14 Gen 2a (20XK) with BIOS 1.33 (R1MET63W): both Type-C connectors register, and plugging and replugging a USB-C monitor with an integrated hub and power delivery brings up DisplayPort Alternate Mode each time. Reported-by: Daniel Dev Closes: https://lore.kernel.org/linux-usb/b1Wn_eFvTFShGbd970WWl4CWhge_6P2x7Wb6rab3QHNlE4OJ4p__O-QN3B6I-308ftr5oV5Zr7vywA0vdvmtNw6E0YJnVM2ek_5DcFnkXB0=@noex.uk/ Fixes: c1b0bc2dabfa ("usb: typec: Add support for UCSI interface") Cc: stable@vger.kernel.org Assisted-by: pi:claude-opus-5-5 Signed-off-by: Stanisław Titenko --- drivers/usb/typec/ucsi/ucsi_acpi.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/usb/typec/ucsi/ucsi_acpi.c b/drivers/usb/typec/ucsi/ucsi_acpi.c index 47ba0e15b8ba..d752fc7b61ec 100644 --- a/drivers/usb/typec/ucsi/ucsi_acpi.c +++ b/drivers/usb/typec/ucsi/ucsi_acpi.c @@ -196,6 +196,22 @@ static const struct dmi_system_id ucsi_acpi_quirks[] = { }, .driver_data = (void *)&ucsi_zero_version_ops, }, + { + /* Lenovo ThinkPad T14 Gen 2a */ + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "LENOVO"), + DMI_MATCH(DMI_BOARD_NAME, "20XK"), + }, + .driver_data = (void *)&ucsi_zero_version_ops, + }, + { + /* Lenovo ThinkPad T14 Gen 2a */ + .matches = { + DMI_MATCH(DMI_BOARD_VENDOR, "LENOVO"), + DMI_MATCH(DMI_BOARD_NAME, "20XL"), + }, + .driver_data = (void *)&ucsi_zero_version_ops, + }, { .matches = { DMI_MATCH(DMI_SYS_VENDOR, "LG Electronics"), -- 2.56.0