On Sat, Jan 17, 2026 at 12:57:58PM +0100, Krzysztof Kozlowski wrote:

On Fri, Jan 16, 2026 at 03:20:58PM -0800, Elson Serrao wrote:

quoted

The Qualcomm Embedded USB Debugger (EUD) hardware can intercept up to
two independent High-Speed UTMI data paths, depending on the SoC
configuration. Each path operates independently with:

- Dedicated PHY interface
- Distinct USB connector and controller associations
- Role dependent routing

Model these hardware paths as separate eud-path nodes to accurately
represent the physical topology and add below per-path properties:

phys: EUD exposes a High-Speed debug hub that relies on HS-PHY for its
operation. This property references the HS-PHY associated with the UTMI
path.

usb-role-switch: Indicates that the USB port on this UTMI path supports
role switching. In device role, debug mode inserts the EUD hub into the
UTMI path. In host role, the EUD hub is bypassed and UTMI traffic flows
directly between the PHY and the USB controller.

This change breaks backwards compatibility, but the previous binding
omitted critical resources like PHY and did not describe per-path
topology. Without these modifications EUD cannot be guaranteed to
function.

It was working for 3 years, so your guarantees are just imprecise. FUD
is not an argument.

Qualcomm task at 2022 was to post complete bindings. These were posted
and accepted. Three years later you say that previous posting was
bollocks and this cannot even work?

That is correct. The description of the hardware that was provided when
this was upstreamed and the binding that was accepted based on this
description is wrong.

There's absolutely a value in maintainting backwards compatibility in
general, but is this one of those cases?

Nah, take responsibility of what you did in the past.

In my view the responsible thing is to accept that we got it wrong and
make sure EUD is enabled end-to-end so people can actually use it.

Regards,
Bjorn