Hi,
On Thu, Oct 23, 2014 at 08:48:08AM -0500, Felipe Balbi wrote:
> On Wed, Oct 22, 2014 at 10:14:54AM -0400, Alan Stern wrote:
> > On Wed, 22 Oct 2014, Anton Tikhomirov wrote:
> >
> > > > That's right, and it's true for USB-2 as well. A ZLP is needed only in
> > > > cases where the host otherwise wouldn't know the transfer is over,
> > > > i.e., when the transfer length is a nonzero multiple of the maxpacket
> > > > size and is smaller than wLength.
> > >
> > > Shall we use/check struct usb_request's zero flag for this?
> >
> > Of course; we have to. There's no other way for the UDC driver to know
> > whether the transfer is shorter than the host expects.
>
> alright, so I take it this incremental diff is enough ?
>
> diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
> index 0a34e71..ce6b0c7 100644
> --- a/drivers/usb/dwc3/ep0.c
> +++ b/drivers/usb/dwc3/ep0.c
> @@ -830,7 +830,8 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
> } else {
> dwc3_gadget_giveback(ep0, r, 0);
>
> - if (IS_ALIGNED(ur->length, ep0->endpoint.maxpacket)) {
> + if (IS_ALIGNED(ur->length, ep0->endpoint.maxpacket) &&
> + ur->zero) {
> int ret;
>
> dwc->ep0_next_event = DWC3_EP0_COMPLETE;
>
here's v2:
8<--------------------------------------------------------------
From 1080b54d66e3e77410b41732e76746ed8e2c01c7 Mon Sep 17 00:00:00 2001
From: Felipe Balbi <balbi@xxxxxx>
Date: Tue, 30 Sep 2014 10:39:14 -0500
Subject: [PATCH] usb: dwc3: ep0: fix Data Phase for transfer sizes aligned to
wMaxPacketSize
According to Section 8.5.3.2 of the USB 2.0 specification,
a USB device must terminate a Data Phase with either a
short packet or a ZLP (if the previous transfer was
a multiple of wMaxPacketSize).
For reference, here's what the USB 2.0 specification, section
8.5.3.2 says:
"
8.5.3.2 Variable-length Data Stage
A control pipe may have a variable-length data phase
in which the host requests more data than is contained
in the specified data structure. When all of the data
structure is returned to the host, the function should
indicate that the Data stage is ended by returning a
packet that is shorter than the MaxPacketSize for the
pipe. If the data structure is an exact multiple of
wMaxPacketSize for the pipe, the function will return
a zero-length packet to indicate the end of the Data
stage.
"
Signed-off-by: Felipe Balbi <balbi@xxxxxx>
---
drivers/usb/dwc3/ep0.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index a47cc1e..ce6b0c7 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -828,12 +828,19 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
dwc3_ep0_stall_and_restart(dwc);
} else {
- /*
- * handle the case where we have to send a zero packet. This
- * seems to be case when req.length > maxpacket. Could it be?
- */
- if (r)
- dwc3_gadget_giveback(ep0, r, 0);
+ dwc3_gadget_giveback(ep0, r, 0);
+
+ if (IS_ALIGNED(ur->length, ep0->endpoint.maxpacket) &&
+ ur->zero) {
+ int ret;
+
+ dwc->ep0_next_event = DWC3_EP0_COMPLETE;
+
+ ret = dwc3_ep0_start_trans(dwc, epnum,
+ dwc->ctrl_req_addr, 0,
+ DWC3_TRBCTL_CONTROL_DATA);
+ WARN_ON(ret < 0);
+ }
}
}
--
2.1.0.GIT
--
balbi
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