> -----Original Message----- > From: Peter Chen [mailto:peter.chen@xxxxxxxxxxxxx] > Sent: 2014年2月25日 9:59 > To: Neil Zhang > Cc: balbi@xxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; linux-usb@xxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx > Subject: Re: [PATCH 3/6] usb: gadget: mv_udc: clear corresponding interrupt > when flush fifo > > On Mon, Feb 24, 2014 at 04:03:13PM +0800, Neil Zhang wrote: > > The interruts are useless when this endpoint is going to be flushed. > > Especially in the enumeration phase, let's take get device description > > for example. > > 1. Device doesn't ACK the status package from host in time due to irq > > is disabled by some module. > > 2. Host find no ACK in time, and send another request. > > Why device does not send NAK at that time? > Besides, you can try to prime status at data stage, it can also avoid the > problem usb 2.0 8.5.3.3 "Error Handling on the Last Data Transaction" > described. > > > 3. Device gets the chance to handle the interrupt, the sequence is as > > following. > > a. Flush pending requests in ep0. > > b. Queue a request in ep0 according to host's request and change > > the ep0 state to DATA_STATE_XMIT. > > c. Handle the pending interrupt for the last status package. But > > actually it will check the new added request instead of the status > > package and because of wront ep0 state, device will request an > > %s/wront/wrong Thanks for the catch. > > Peter > > > unexpected status package from host. > > d. The ep0 state is going mad. > > > > The solution is that we need clear the pending corresponding interrupt > > as well as flush endpoint. > > > > Signed-off-by: Neil Zhang <zhangwm@xxxxxxxxxxx> > > --- > > drivers/usb/gadget/mv_udc_core.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/usb/gadget/mv_udc_core.c > > b/drivers/usb/gadget/mv_udc_core.c > > index 657ac5c..d5a9bdf 100644 > > --- a/drivers/usb/gadget/mv_udc_core.c > > +++ b/drivers/usb/gadget/mv_udc_core.c > > @@ -692,6 +692,8 @@ static void mv_ep_fifo_flush(struct usb_ep *_ep) > > } > > loops--; > > } while (readl(&udc->op_regs->epstatus) & bit_pos); > > + > > + writel(bit_pos, &udc->op_regs->epcomplete); > > } > > > > /* queues (submits) an I/O request to an endpoint */ > > -- > > 1.7.9.5 > > > > -- > > 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 > > > > > Best Regards, Neil Zhang > -- > > Best Regards, > Peter Chen ?韬{.n?????%??檩??w?{.n???{炳???骅w* jg????????G??⒏ ⒎?:+v???????? ????＂??????
