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 | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/drivers/usb/gadget/udc/dummy_hcd.c b/drivers/usb/gadget/udc/dummy_hcd.c
index 552c533..0ba0ab3 100644
--- a/drivers/usb/gadget/udc/dummy_hcd.c
+++ b/drivers/usb/gadget/udc/dummy_hcd.c
@@ -1288,6 +1288,7 @@ top:
/* if there's no request queued, the device is NAKing; return */
list_for_each_entry(req, &ep->queue, queue) {
unsigned host_len, dev_len, len;
+ unsigned quot, rem;
int is_short, to_host;
int rescan = 0;
@@ -1324,12 +1325,18 @@ 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 */
+ rem = len % ep->ep.maxpacket;
+ quot = len - rem;
+ if (quot > 0) {
+ is_short = 0;
+ len = quot;
+ if (rem > 0)
+ rescan = 1;
+ } else { /* rem > 0 */
+ is_short = 1;
+ len = rem;
}
- is_short = (len % ep->ep.maxpacket) != 0;
len = dummy_perform_transfer(urb, req, len);
--
1.9.1
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