[lkml]   [2016]   [Apr]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRE: [PATCH] usb: dwc3: usb/dwc3: fake dissconnect event when turn off pullup


(we don't top-post on this forum ;-)

"Du, Changbin" <> writes:
> Hi, Balbi,
> The step to reproduce this issue is:
> 1) connect device to a host and wait its enumeration.
> 2) trigger software disconnect by calling function
> usb_gadget_disconnect(), which finally call
> dwc3_gadget_pullup(false). Do not reconnect device
> (I mean no enumeration go on, keep bit Run/Stop 0.).
> At here, gadget driver's disconnect callback should be
> Called, right? We has been disconnected. But no, as
> You said " not generating disconnect IRQ after you
> drop Run/Stop is expected".
> And I am testing on an Android device, Android only
> use dwc3_gadget_pullup(false) to issue a soft disconnection.
> This confused user that the UI still show usb as connected
> State, caused by missing a disconnect event.

okay, so I know what this is. This is caused by Android gadget itself
not notifying the gadget that a disconnect has happened. Just look at
udc-core's soft_connect implementation for the sysfs interface, and
you'll see what I mean.

This should be fixed at Android gadget itself. The only thing we could
do is introduce a new usb_gadget_soft_connect()/disconnect() to wrap the
logic so it's easier for Android gadget to use; but even that I'm a
little bit reluctant to do because Android should be using our
soft_connect interface instead of reimplementing it (wrongly) by its

[unhandled content-type:application/pgp-signature]
 \ /
  Last update: 2016-04-28 09:21    [W:0.096 / U:3.904 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site