Hello. On 22-11-2010 13:02, 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
Linus has asked to also specify the commit summary in parens.
Ok I will do this if the patch is with regards to its content ok.
It's does not seem OK currently...
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);
No, really you shouldn't send null data in every case when req->req.length - ep->sent<= 0, only if req->req.length == 0 or req->req.zero == 1...
Hm, yes this piece of code looks a bit odd to me too. And I did not understand what it should solve. But I let it untouched, because the bug my patch should fix is in my eyes a different topic.
No, this is actually the same topic.
+ if (req->req.zero&& (req->req.length == USB_EP0_MAX_SIZE))
Not (req->req.length % USB_EP0_MAX_SIZE == 0)? Also, you should probably check that ep->sent == req->req.length here...
No not (req->req.length % USB_EP0_MAX_SIZE == 0), because the nulldata which is missing should only be send if it is the last packet of a frame and not every
But your code will only send nulldata is the transfer is *exactly* 64 bytes. req->req.length shouldn't change.
time a 64byte packet is send.
You've misunderstood what I proposed -- there's no way it can send nulldata for each 64 packet. That's why we should check that (ep->sent == req->req.length).
Best regards Holger
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