This is a note to let you know that I've just added the patch titled
usb: gadget: fsl_udc_core: dTD's next dtd pointer need to be updated once
written
to the 3.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-gadget-fsl_udc_core-dtd-s-next-dtd-pointer-need-to-be-updated-once-written.patch
and it can be found in the queue-3.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 4d0947dec4db1224354e2f6f00ae22ce38e62a43 Mon Sep 17 00:00:00 2001
From: Peter Chen <[email protected]>
Date: Sun, 1 Apr 2012 15:17:16 +0800
Subject: usb: gadget: fsl_udc_core: dTD's next dtd pointer need to be updated
once written
From: Peter Chen <[email protected]>
commit 4d0947dec4db1224354e2f6f00ae22ce38e62a43 upstream.
dTD's next dtd pointer need to be updated once CPU writes it, or this
request may not be handled by controller, then host will get NAK from
device forever.
This problem occurs when there is a request is handling, we need to add
a new request to dTD list, if this new request is added before the current
one is finished, the new request is intended to added as next dtd pointer
at current dTD, but without wmb(), the dTD's next dtd pointer may not be
updated when the controller reads it. In that case, the controller will
still get Terminate Bit is 1 at dTD's next dtd pointer, that means there is
no next request, then this new request is missed by controller.
Signed-off-by: Peter Chen <[email protected]>
Acked-by: Li Yang <[email protected]>
Signed-off-by: Felipe Balbi <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/usb/gadget/fsl_udc_core.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/usb/gadget/fsl_udc_core.c
+++ b/drivers/usb/gadget/fsl_udc_core.c
@@ -737,6 +737,8 @@ static void fsl_queue_td(struct fsl_ep *
lastreq = list_entry(ep->queue.prev, struct fsl_req, queue);
lastreq->tail->next_td_ptr =
cpu_to_hc32(req->head->td_dma & DTD_ADDR_MASK);
+ /* Ensure dTD's next dtd pointer to be updated */
+ wmb();
/* Read prime bit, if 1 goto done */
if (fsl_readl(&dr_regs->endpointprime) & bitmask)
return;
Patches currently in stable-queue which might be from [email protected]
are
queue-3.3/usb-gadget-fsl_udc_core-dtd-s-next-dtd-pointer-need-to-be-updated-once-written.patch
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