Re: [RFC][PATCH] usb: dwc2: Make sure we disconnect the gadget state

[John Youn]

On 2/13/2017 8:08 PM, John Stultz wrote:
> Just wanted to get some early feedback on this before I submit
> it for real for the 4.12 timeframe. This is the last patch, that
> isn't already queued, which I need to get hikey's USB working
> properly.
>
> Feedback would be greatly appreciated!
>


It looks good to me.

Acked-by: John Youn <johnyoun@xxxxxxxxxxxx>

Regards,
John



> thanks
> -john
>
>
> I had seen some odd behavior with HiKey's usb-gadget interface
> that I finally seemed to have chased down. Basically every other
> time I pluged in the OTG port, the gadget interface would
> properly initialize. The other times, I'd get a big WARN_ON
> in dwc2_hsotg_init_fifo() about the fifo_map not being clear.
>
> Ends up if we don't disconnect the gadget state, the fifo-map
> doesn't get cleared properly, which causes WARN_ON messages and
> also results in the device not properly being setup as a gadget
> every other time the OTG port is connected.
>
> So this patch adds a call to dwc2_hsotg_disconnect() in the
> reset path so the state is properly cleared.
>
> With it, the gadget interface initializes properly on every
> plug in.
>
> Cc: Wei Xu <xuwei5@xxxxxxxxxxxxx>
> Cc: Guodong Xu <guodong.xu@xxxxxxxxxx>
> Cc: Amit Pundir <amit.pundir@xxxxxxxxxx>
> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> Cc: John Youn <johnyoun@xxxxxxxxxxxx>
> Cc: Douglas Anderson <dianders@xxxxxxxxxxxx>
> Cc: Chen Yu <chenyu56@xxxxxxxxxx>
> Cc: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: linux-usb@xxxxxxxxxxxxxxx
> Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
> ---
>  drivers/usb/dwc2/hcd.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
> index 90bd248..067202d 100644
> --- a/drivers/usb/dwc2/hcd.c
> +++ b/drivers/usb/dwc2/hcd.c
> @@ -3266,6 +3266,7 @@ static void dwc2_conn_id_status_change(struct work_struct *work)
>  		dwc2_core_init(hsotg, false);
>  		dwc2_enable_global_interrupts(hsotg);
>  		spin_lock_irqsave(&hsotg->lock, flags);
> +		dwc2_hsotg_disconnect(hsotg);
>  		dwc2_hsotg_core_init_disconnected(hsotg, false);
>  		spin_unlock_irqrestore(&hsotg->lock, flags);
>  		dwc2_hsotg_core_connect(hsotg);
>