USB3 regression in RK3399

[Heiko Stuebner]

Hi Vicente,

Am Mittwoch, 21. Februar 2018, 22:58:35 CET schrieb Vicente Bergas:
> testing on the Sapphire board, which uses the RK3399 SoC, a regression
> has been found in v4.16-rc2 wrt v4.15.4 regarding the USB3 type-A port:
> In v4.15.4 it works in USB2-only mode.
> In v4.16-rc2 it does not work.
> 
> It has been tested with a USB2 hub with 3 devices connected:
> a keyboard (USB1.1), a mouse (USB2) and a rtlwifi dongle (USB2).
> 
> It has also been tested with a USB3-to-SATA converter. This one is not
> working in v4.15.4 nor in v4.16-rc2.
> 
> I have also tried the 6-patch series from Enric Balletbo i Serra
> "[PATCH v3 3/6] phy: rockchip-typec: enable usb3 host during usb3 phy power on"
> with the same result.
> 
> During boot, the following message appears a few times:
> "dwc3: failed to initialize core"
> 
> The kernel configuration is:
> https://archlinuxarm.org/packages/aarch64/linux-aarch64-rc/files/config
> 
> Is that a configuration issue, a bug in the kernel or something else?
> If it is a configuration issue, what should be changed?
> If it is a bug, can it be fixed?

Hmm, I'd guess the main issue would be a missing typec-phy driver
in your kernel (see drivers/phy/rockchip/phy-rockchip-typec.c

But even with this driver, I realize that we'll be missing the extcon
driver telling the driver about the cable state. ChromeOS devices
get the cable-state from the embedded controller via the extcon
interface and while other boards seem to use the fusb302 chip
for power-delivery, the driver currently does not seem to
utilize the extcon interface for something like this.

Also, right now the rockchip typec-phy does fail probing when no
extcon is detected, but shouldn't it just fall back to working in host-
mode if it cannot get the extcon, or the device just routes everything
to a standard usb3 port?

Heiko