On Tue, 15 Sep 2015, Igor Kotrasinski wrote:
> transfer() schedules a rescan for transfers larger than
> maxpacket, which is wrong for transfers that are multiples
> of maxpacket.
>
> Rewrite to fix and clarify packet multiple / remainder
> transfer logic.
>
> Signed-off-by: Igor Kotrasinski <i.kotrasinsk@xxxxxxxxxxx>
> ---
> drivers/usb/gadget/udc/dummy_hcd.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/usb/gadget/udc/dummy_hcd.c b/drivers/usb/gadget/udc/dummy_hcd.c
> index da38475..2ecec06a 100644
> --- a/drivers/usb/gadget/udc/dummy_hcd.c
> +++ b/drivers/usb/gadget/udc/dummy_hcd.c
> @@ -1320,12 +1320,15 @@ top:
> if (len == 0)
> break;
>
> - /* use an extra pass for the final short packet */
> - if (len > ep->ep.maxpacket) {
> - rescan = 1;
> - len -= (len % ep->ep.maxpacket);
> + /* send multiple of maxpacket first, then remainder */
> + if (len >= ep->ep.maxpacket) {
> + is_short = 0;
> + if (len % ep->ep.maxpacket)
> + rescan = 1;
> + len -= len % ep->ep.maxpacket;
> + } else {
> + is_short = 1;
> }
> - is_short = (len % ep->ep.maxpacket) != 0;
>
> len = dummy_perform_transfer(urb, req, len);
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
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