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The DWC3 rockchip driver provides a sysfs interface "dwc3_mode" to force Peripheral mode or Host mode. It has a problem to force to Host mode when the DWC3 works as Peripheral mode and connects to Host (e.g. PC USB Port). This issue can be reproduced on RK1808 EVB follow these steps: 1. Set dr_mode = "otg" in DTS dwc3 node; 2. Start the system, and connect the RK1808 USB 3.0 to PC USB. 3. Make sure that PC has recognized the USB device, and then force DWC3 to Host mode via "dwc3_mode". echo "host" > /sys/devices/platform/usb/dwc3_mode And plug in an USB 2.0 Device to RK1808 USB 3.0 Port, then we can see the following error log: rockchip-dwc3 usb: Peripheral disconnect timeout rockchip-dwc3 usb: USB unconnectedxhci-hcd xhci-hcd.3.auto: xHCI Host Controller xhci-hcd xhci-hcd.3.auto: new USB bus registered, assigned bus number 3 xhci-hcd xhci-hcd.3.auto: hcc params 0x0220fe64 hci version 0x110 quirks 0x04010010 ... hub 4-0:1.0: USB hub found hub 4-0:1.0: 1 port detected rockchip-dwc3 usb: USB HOST connected rockchip-dwc3 usb: set new mode successfully usb 3-1: new high-speed USB device number 2 using xhci-hcd usb 3-1: new high-speed USB device number 3 using xhci-hcd usb usb3-port1: attempt power cycle usb 3-1: new full-speed USB device number 4 using xhci-hcd usb 3-1: Device not responding to setup address usb 3-1: Device not responding to setup address usb 3-1: device not accepting address 4, error -71 It's because that in this test case, the dr_mode is original otg mode, and the current code only call phy_set_mode() to disconnect the peripheral from PC host if the dr_mode is peripheral mode. This cause dwc3_rockchip_otg_extcon_evt_work() wait peripheral disconnect timeout, and DWC3 fail to do runtime suspend and resume to initialized the DWC3 core register again. This patch call phy_set_mode() to disconnect the peripheral if the current dr_mode is peripheral or otg when force to host mode. Change-Id: I733d364046abcb616cf3d99ed57ab8604a87eef6 Signed-off-by: William Wu <william.wu@rock-chips.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.