On Mon, 23 Jan 2012, Sebastian Andrzej Siewior wrote: > The following scenario: > - use a third party tool > - issue SetConfiguration, start a transfer > - g_zero enqueues 4k reqs. Be rude and stop after a multiple of maxpacketsize > but before the 4k > - Assume the UDC can handle 4k transfer in one go and will interrupt after the > 4k arrived or a short transfer. That the transfer is still "busy". > - now soft the disconnect the device. > - the UDC gets a SetConfiguration 0 and will disable all endpoints > - disabling an endpoint means cancles all pending transfers. > > On DWC3 we issue a cancel transfer command and wait for the command/transfer to > complete. Do you mean you _don't_ wait for the transfer to complete? > That means we return immediately from ->disable(). The _gadget_ has to > wait for the ->complete() callback. g_zero does not and the result is: This patch is wrong; DWC3 must be fixed instead. From include/linux/usb/gadget.h: /** * usb_ep_disable - endpoint is no longer usable * @ep:the endpoint being unconfigured. may not be the endpoint named "ep0". * * no other task may be using this endpoint when this is called. * any pending and uncompleted requests will complete with status * indicating disconnect (-ESHUTDOWN) before this call returns. * gadget drivers must call usb_ep_enable() again before queueing * requests to the endpoint. * * returns zero, or a negative error code. */ Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
