-----Original Message-----
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Sent: Thursday, December 9, 2021 8:05 AM
To: Neal Liu <neal_liu@aspeedtech.com>; Felipe Balbi <balbi@kernel.org>;
Greg Kroah-Hartman [off-list ref]; Joel Stanley
[off-list ref]; Andrew Jeffery [off-list ref]; Cai Huoqing
[off-list ref]; Tao Ren [off-list ref]; Julia Lawall
[off-list ref]; kernel test robot [off-list ref]; Sasha Levin
[off-list ref]; linux-usb@vger.kernel.org; linux-kernel@vger.kernel.org;
linux-arm-kernel@lists.infradead.org; linux-aspeed@lists.ozlabs.org
Cc: BMC-SW <redacted>
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:

quoted

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@aspeedtech.com>

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

quoted

---
 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",

quoted

 	       u_req->length, (u32)u_req->dma, u_req->zero,