Re: [PATCH 2/5] usb: typec: ps883x: Return -EOPNOTSUPP for USB4 when parade,disable-usb4 is set

From: Jens Glathe

Date: Wed Jul 22 2026 - 04:54:15 EST


Hi,

On 7/21/26 19:57, Dmitry Baryshkov wrote:
On Sat, Jul 18, 2026 at 07:06:30PM +0200, Jens Glathe via B4 Relay wrote:
From: Jens Glathe <jens.glathe@xxxxxxxxxxxxxxxxxxxxxx>

On Qualcomm X1E80100 platforms using the Parade PS883x retimer (like
Lenovo ThinkPad T14s Gen6), hotplugging USB4-capable docks such as the
Lenovo 40B0 results in working USB but no DisplayPort output on the
dock's HDMI/DP ports.

When the dock negotiates USB4, the retimer receives TYPEC_MODE_USB4
and forwards it via typec_mux_set(). The qmp_combo PHY then selects
QMPPHY_MODE_USB3_ONLY because no classic DP altmode SVID is present in
the state, leaving the DP transmitter and AUX channel disabled.
Would it be enough to make QMP combo PHY to treat USB4 as USB3+DP for
the sake of this issue?
AFAIU, no. USB4 has some tunneling protocol for DP altmode, not dedicated lanes. Therefore you need to either support that or enforce USB3 DP altmode negotiation. The role-switch on the qmmphy would be too late IMO.

with best regards

Jens