This is a note to let you know that I've just added the patch titled
usb: chipidea: udc: don't stall endpoint if request list is empty in
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-next branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will also be merged in the next major kernel release
during the merge window.
If you have any questions about this process, please let me know.
>From db89960e50f45274c07dc60926b5a49489b8a7a0 Mon Sep 17 00:00:00 2001
From: Michael Grzeschik <[email protected]>
Date: Wed, 12 Sep 2012 14:58:04 +0300
Subject: usb: chipidea: udc: don't stall endpoint if request list is empty in
isr_tr_complete_low
When attaching an imx28 or imx53 in USB gadget mode to a Windows host and
starting a rndis connection we see this message every 4-10 seconds:
g_ether gadget: high speed config #2: RNDIS
Analysis shows that each time this message is printed, the rndis connection is
re-establish due to a reset because of a stalled endpoint (ep 0, dir 1). The
endpoint is stalled because the reqeust complete bit on that endpoint is set,
but in isr_tr_complete_low() the endpoint request list (mEp->qh.queue) is
empty.
This patch removed this check, because the code doesn't take the following
situation into account:
The loop over all endpoints in isr_tr_complete_handler() will call ep_nuke() on
both ep0/dir0 and ep/dir1 in the first loop. Pending reqeusts will be flushed
and completed here. There seems to be a race condition, the request is nuked,
but the request complete bit will be set, too. The subsequent check (in
ep0/dir1's loop cycle) for endpoint request list (mEp->qh.queue) empty will
fail.
Both other mainline chipidea drivers (mv_udc_core.c and fsl_udc_core.c) don't
have this check.
Cc: stable <[email protected]>
Signed-off-by: Michael Grzeschik <[email protected]>
Signed-off-by: Marc Kleine-Budde <[email protected]>
Signed-off-by: Alexander Shishkin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/usb/chipidea/udc.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
index 2d8b609..d214448 100644
--- a/drivers/usb/chipidea/udc.c
+++ b/drivers/usb/chipidea/udc.c
@@ -771,10 +771,7 @@ __acquires(mEp->lock)
{
struct ci13xxx_req *mReq, *mReqTemp;
struct ci13xxx_ep *mEpTemp = mEp;
- int uninitialized_var(retval);
-
- if (list_empty(&mEp->qh.queue))
- return -EINVAL;
+ int retval = 0;
list_for_each_entry_safe(mReq, mReqTemp, &mEp->qh.queue,
queue) {
--
1.7.12.176.g3fc0e4c
--
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