tree 5dededf24ec2477e214bbd92cf288f069f344fb9
parent d9eadbba6663a5361699310959422a85e128e416
author Jens Glathe <jens.glathe@oldschoolsolutions.biz> 1790079931 +0200
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1790831724 +0200

usb: typec: mux: ps883x: disable USB4 on incomplete USB4 platforms

On Qualcomm X1E80100 / X1P42100 platforms using the Parade PS883x
retimer, hotplugging USB4-capable docks such as the Lenovo 40B0 can
result in working USB but no DisplayPort output.

When the dock negotiates USB4, the retimer receives TYPEC_MODE_USB4
and forwards it via typec_mux_set(). The qmp-combo PHY then selects
USB3-only because no classic DP altmode SVID is present in the state,
leaving the DP transmitter and AUX channel disabled.

Reject USB4 with -EOPNOTSUPP on platforms whose USB4 / DP-tunneling
stack is not ready yet. The Type-C stack then falls back to USB3 + DP
Alt Mode. DP altmode configuration continues to use the existing
ps883x_set() path.

Use a machine-compatible table rather than a DT property so the quirk
stays inside the kernel and can be removed later without creating ABI.

Assisted-by: Grok(xAI):4.6
Tested-by: Dr. David Alan Gilbert <dave@treblig.org>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Jens Glathe <jens.glathe@oldschoolsolutions.biz>
Link: https://patch.msgid.link/20260922-ps883x-disable-usb4-v5-3-02c0414978e6@oldschoolsolutions.biz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>