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Subject: Re: [PATCH v2 1/2] usb: dwc2: host: Fix missing device insertions
From: Julius Werner <jwerner@chromium.org>
To: Doug Anderson <dianders@chromium.org>
Cc: Alan Stern <stern@rowland.harvard.edu>, Felipe Balbi <balbi@ti.com>,
        John Youn <John.Youn@synopsys.com>, Yunzhi Li <lyz@rock-chips.com>,
        =?UTF-8?Q?Heiko_St=C3=BCbner?= <heiko@sntech.de>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@lists.infradead.org>,
        Julius Werner <jwerner@chromium.org>,
        "Herrero, Gregory" <gregory.herrero@intel.com>,
        "Kaukab, Yousaf" <yousaf.kaukab@intel.com>,
        Dinh Nguyen <dinguyen@opensource.altera.com>,
        John Youn <johnyoun@synopsys.com>,
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        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
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Another point to note, which I think is what prevents the flow Alan
suggested from working, is this little snippet in DWC2's hub_control
GetPortStatus callback:

                if (!hsotg->flags.b.port_connect_status) {
                        /*
                         * The port is disconnected, which means the core is
                         * either in device mode or it soon will be.
Just
                         * return 0's for the remainder of the port status
                         * since the port register can't be read if the core
                         * is in device mode.
                         */
                        *(__le32 *)buf = cpu_to_le32(port_status);
                        break;
                }

This is before it actually checks the register state of the port. So
it relies on dwc2_hcd_connect() and dwc2_hcd_disconnect() to be called
in the right order to give the correct answer for
USB_PORT_STAT_CONNECTION. This could maybe be improved but I don't
know what kind of weird interactions with device mode operation made
that snippet necessary in the first place.