On 1/26/2026 11:22 AM, Chaoyi Chen wrote: > Hello, > > On 1/26/2026 3:42 AM, Hugh Cole-Baker wrote: >> On 19/01/2026 07:30, Chaoyi Chen wrote: >>> From: Chaoyi Chen <[email protected]> >>> >>> This series focuses on adding Type-C DP support for USBDP PHY and DP >>> driver. The USBDP PHY and DP will perceive the changes in cable status >>> based on the USB PD and Type-C state machines provided by TCPM. Before >>> this, the USBDP PHY and DP controller of RK3399 sensed cable state >>> changes through extcon, and devices such as the RK3399 Gru-Chromebook >>> rely on them. This series should not break them. >>> >>> ==== >>> 1. DisplayPort HPD status notify >>> >>> Before v7, I implemented a variety of DP HPD status notify. However, >>> they all had various problems and it was difficult to become a generic >>> solution. >>> >>> Under the guidance of Heikki and Dmitry, a decoupled notification >>> method between the TypeC and DRM subsystems was introduced in v7. >>> First, a notification is sent when TypeC registers a new altmode. >>> Then, a generic DP AUX HPD bridge is implemented on the DRM side. >>> >>> During v7-v10, we added a new notifier in typec to notify the altmode >>> device register event. With the help of Greg and Heikki, we implemented >>> the reuse of notifiers for the type bus itself in patch1 of v11. >>> >>> The USB subsystem related parts have already been merged into the >>> usb-next branch in v13 [0][1]. Therefore, this series no longer includes >>> these patches starting from v14. Thanks to Greg and Heikki! >>> >>> [0]: >>> https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git/commit/?h=usb-next&id=67ab45426215c7fdccb65aecd4cac15bbe4dfcbb >>> [1]: >>> https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git/commit/?h=usb-next&id=4dee13db29de6dd869af9b3827e1ff569644e838 >>> >>> That makes it redundant for each Type-C controller driver to implement >>> a similar DP AUX HPD bridge in embedded scenarios. >>> >>> ==== >>> 2. Altmode switching and orientation switching for USBDP PHY >>> >>> For USB Type-C interfaces, an external Type-C controller chip assists >>> by detecting cable attachment, determining plug orientation, and >>> reporting USB PD message. The USB/DP combo PHY supports software >>> configurable pin mapping and DisplayPort lane assignment. Based on >>> these message, the combo PHY can perform both altmode switching and >>> orientation switching via software. >>> >>> The RK3399 EVB IND board has a Type-C interface DisplayPort. It use >>> fusb302 chip as Type-C controller. The connection diagram is shown below: >>> >>> fusb302 chip +---> USB2.0 PHY ----> DWC3 USB controller >>> | >>> +---> USB/DP PHY0 +--> CDN-DP controller >>> | >>> +--> DWC3 USB controller >>> >>> ==== >>> 3. Multiple bridge model for RK3399 CDN-DP >>> >>> The RK3399 has two USB/DP combo PHY and one CDN-DP controller. And >>> the CDN-DP can be switched to output to one of the PHYs. >>> >>> USB/DP PHY0 ---+ >>> | <----> CDN-DP controller >>> USB/DP PHY1 ---+ >>> >>> In previous versions, if both PHY ports were connected to DP, >>> the CDN-DP driver would select the first PHY port for output. >>> >>> On Dmitry's suggestion, we introduced a multi-bridge model to support >>> flexible selection of the output PHY port. For each PHY port, a >>> separate encoder and bridge are registered. >>> >>> The change is based on the DRM AUX HPD bridge, rather than the >>> extcon approach. This requires the DT to correctly describe the >>> connections between the first bridge in bridge chain and DP >>> controller. And Once the first bridge is obtained, we can get the >>> last bridge corresponding to the USB-C connector, and then set the >>> DRM connector's fwnode to the corresponding one to enable HPD >>> notification. >> >> With a similar dts patch [1] on top of this series I tested a type-C to >> DP adapter/cable for display output on the ROCKPro64 board, which also >> pairs a FUSB302 with RK3399. Booting it up with the cable plugged in >> works, as does hotplugging the cable after booting in both orientations. >> The correct mode for the display is detected. I wasn't able to test >> audio, only video output, as this display doesn't have speakers. >> >> I did once, after unplugging and reconnecting the cable a few times, >> see it get into a state where it didn't detect the attached display. >> Logs from that unplug/reconnect attempt are here [2] if of interest. >> Nevertheless, hotplug seems to work the majority of the time, so >> >> Tested-by: Hugh Cole-Baker <[email protected]> >> >> [1]: >> https://github.com/sigmaris/linux/commit/91724088b19bee7d248946442a801423e8cd0634 >> [2]: https://gist.github.com/sigmaris/fa107384a7492583ceee1c2962f5030a >> > > Thank you for the test. I also have the same board, and I will > try it later :) >
I just tested on the ROCKPro64 board using a Type-C to HDMI dock, and after repeatedly plugging and unplugging it over 30 times, it performed correctly every time :) -- Best, Chaoyi
