> -----Original Message----- > From: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> > Sent: Thursday, December 9, 2021 8:05 AM > To: Neal Liu <neal_liu@xxxxxxxxxxxxxx>; Felipe Balbi <balbi@xxxxxxxxxx>; > Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>; Joel Stanley > <joel@xxxxxxxxx>; Andrew Jeffery <andrew@xxxxxxxx>; Cai Huoqing > <caihuoqing@xxxxxxxxx>; Tao Ren <rentao.bupt@xxxxxxxxx>; Julia Lawall > <julia.lawall@xxxxxxxx>; kernel test robot <lkp@xxxxxxxxx>; Sasha Levin > <sashal@xxxxxxxxxx>; linux-usb@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-aspeed@xxxxxxxxxxxxxxxx > Cc: BMC-SW <BMC-SW@xxxxxxxxxxxxxx> > Subject: Re: [PATCH v3 2/4] usb: aspeed-vhub: fix remote wakeup failure in > iKVM use case > > On Wed, 2021-12-08 at 18:05 +0800, Neal Liu wrote: > > Signaling remote wakeup if an emulated USB device has any activity if > > the device is allowed by host. > > > > Signed-off-by: Neal Liu <neal_liu@xxxxxxxxxxxxxx> > > I still think it should fundamentally be the device making that decision, but > since they don't, this is an acceptable workaround, but please, don't write the > MMIO on every EP queue. Either keep track of the bus being suspended, or > turn on the AUTO bit in HW when wakeup_en is set. > > Cheers, > Ben. > I'm confused. Signaling Wakeup when wakeup_en is set if it has any ep activities is not exactly what you said? wakeup_en is set only if host allows this device have wakeup capability and bus being suspended. Normal ep activities would not write the MMIO because wakeup_en is not set. Thanks -Neal > > --- > > drivers/usb/gadget/udc/aspeed-vhub/epn.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/drivers/usb/gadget/udc/aspeed-vhub/epn.c > > b/drivers/usb/gadget/udc/aspeed-vhub/epn.c > > index 917892ca8753..ccc239b5cc17 100644 > > --- a/drivers/usb/gadget/udc/aspeed-vhub/epn.c > > +++ b/drivers/usb/gadget/udc/aspeed-vhub/epn.c > > @@ -381,6 +381,11 @@ static int ast_vhub_epn_queue(struct usb_ep* > > u_ep, struct usb_request *u_req, > > } else > > u_req->dma = 0; > > > > + if (ep->dev->wakeup_en) { > > + EPVDBG(ep, "Wakeup host first\n"); > > + ast_vhub_hub_wake_all(vhub); > > + } > > + > > EPVDBG(ep, "enqueue req @%p\n", req); > > EPVDBG(ep, " l=%d dma=0x%x zero=%d noshort=%d noirq=%d > is_in=%d\n", > > u_req->length, (u32)u_req->dma, u_req->zero,