I've found when booting HiKey with the usb gadget cable attached if I then try to connect via adb, I get an infinite spew of:
dwc2 f72c0000.usb: dwc2_hsotg_ep_sethalt(ep ffffffc0790ecb18 ep1out, 0) dwc2 f72c0000.usb: dwc2_hsotg_ep_sethalt(ep ffffffc0790eca18 ep1in, 0) It seems that the usb autosuspend is suspending the bus shortly after bootup when the gadget cable is attached. So when adbd then tries to use the device, it doesn't work and it then tries to restart it over and over via the ep_sethalt calls (via FUNCTIONFS_CLEAR_HALT ioctl). Chen Yu suggested this patch to avoid suspending if we're in device mode, and it avoids the problem. This doesn't remove the need for the previous patch, to resume the port when we switch to gadget mode from host mode. But it does seem to resolve the issue. Cc: Wei Xu <[email protected]> Cc: Guodong Xu <[email protected]> Cc: Amit Pundir <[email protected]> Cc: Rob Herring <[email protected]> Cc: John Youn <[email protected]> Cc: Douglas Anderson <[email protected]> Cc: Chen Yu <[email protected]> Cc: Felipe Balbi <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: [email protected] Suggested-by: Chen Yu <[email protected]> Signed-off-by: John Stultz <[email protected]> --- drivers/usb/dwc2/hcd.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c index 61eea70..75ddfa3 100644 --- a/drivers/usb/dwc2/hcd.c +++ b/drivers/usb/dwc2/hcd.c @@ -4386,6 +4386,9 @@ static int _dwc2_hcd_suspend(struct usb_hcd *hcd) if (!HCD_HW_ACCESSIBLE(hcd)) goto unlock; + if (hsotg->op_state == OTG_STATE_B_PERIPHERAL) + goto unlock; + if (!hsotg->core_params->hibernation) goto skip_power_saving; -- 2.7.4
