From: Ming Lei <tom.leiming@xxxxxxxxx>
This patch fixes the problem reported by Sergei:
>how come? we need to send ZLP before giving back the request.
>Well, look at the code ionce again. We need to send ZLP *after*
>request->actual == request->length, but as the check is inserted
>after the ZLP send, ZLP *may* be sent once the first DMA completes,
>not the last.
The patch also has been discussed on the link below:
http://marc.info/?t=128454814900001&r=1&w=2
Signed-off-by: Ming Lei <tom.leiming@xxxxxxxxx>
Reported-by: Sergei Shtylyov <sshtylyov@xxxxxxxxxx>
Cc: Felipe Balbi <balbi@xxxxxx>
Cc: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Cc: Anand Gadiyar <gadiyar@xxxxxx>
Cc: Mike Frysinger <vapier@xxxxxxxxxx>
Cc: Sergei Shtylyov <sshtylyov@xxxxxxxxxxxxx>
---
This patch is against the "patch-2.6.36+" patchset
sent out by Felipe on Sept. 16.
---
drivers/usb/musb/musb_gadget.c | 22 +++++++++++++---------
1 files changed, 13 insertions(+), 9 deletions(-)
diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index 46cf94a..36b6042 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -477,7 +477,13 @@ void musb_g_tx(struct musb *musb, u8 epnum)
epnum, csr, musb_ep->dma->actual_len, request);
}
- if (is_dma || request->actual == request->length) {
+ /*
+ * We should do the followings only if data transfer for
+ * the 'request' is over:
+ * - handle ZLP or short packet if meeting the conditions
+ * - complete the request
+ */
+ if (request->actual == request->length) {
/*
* First, maybe a terminating short packet. Some DMA
* engines might handle this by themselves.
@@ -503,14 +509,12 @@ void musb_g_tx(struct musb *musb, u8 epnum)
request->zero = 0;
}
- if (request->actual == request->length) {
- musb_g_giveback(musb_ep, request, 0);
- request = musb_ep->desc ? next_request(musb_ep) : NULL;
- if (!request) {
- DBG(4, "%s idle now\n",
- musb_ep->end_point.name);
- return;
- }
+ musb_g_giveback(musb_ep, request, 0);
+ request = musb_ep->desc ? next_request(musb_ep) : NULL;
+ if (!request) {
+ DBG(4, "%s idle now\n",
+ musb_ep->end_point.name);
+ return;
}
}
--
1.6.2.5
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