On Fri, 19 Nov 2010, Holger brunck wrote: > From: Stefan Bigler <stefan.bigler@xxxxxxxxxxx> > > Some usb serial host drivers expect a short packet before they forward > the data to the application. This is caused by them trying to read more > than one packet at a time. So when the gadget sends an exact multiple > of the maximum packet size, it should append a zero-length packet. > The gadget driver for fsl_qe was not handling this case correctly. > This patch adds sending of a null packet if it is the last packet of > a frame and the request length is USB_EP0_MAX_SIZE (64 Byte). > > See also commit 2e25134122c25ebb0679b4bbd536fb46c669f9d7 > > Signed-off-by: Stefan Bigler <stefan.bigler@xxxxxxxxxxx> > Signed-off-by: Holger Brunck <holger.brunck@xxxxxxxxxxx> > Cc: Li Yang <leoli@xxxxxxxxxxxxx> > Cc: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx> > > --- > drivers/usb/gadget/fsl_qe_udc.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/drivers/usb/gadget/fsl_qe_udc.c b/drivers/usb/gadget/fsl_qe_udc.c > index 7881f12..279454a 100644 > --- a/drivers/usb/gadget/fsl_qe_udc.c > +++ b/drivers/usb/gadget/fsl_qe_udc.c > @@ -1229,6 +1229,9 @@ static int frame_create_tx(struct qe_ep *ep, struct qe_frame *frame) > else > reval = sendnulldata(ep, frame, 0); > > + if (req->req.zero && (req->req.length == USB_EP0_MAX_SIZE)) > + reval = sendnulldata(ep, frame, 0); > + > return reval; > } The patch description doesn't seem to match what the new code does. The new code doesn't check whether this is the last transfer in a frame, and it only checks whether the request length is _equal_ to the maxpacket size -- not whether it is a _multiple_ of the maxpacket size. 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
