This is a note to let you know that I've just added the patch titled
usb: dwc3: gadget: Stop TRB preparation after limit is reached
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-linus 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 hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From 39e60635a01520e8c8ed3946a28c2b98e6a46f79 Mon Sep 17 00:00:00 2001
From: Amit Virdi <amit.virdi@xxxxxx>
Date: Tue, 13 Jan 2015 14:27:21 +0530
Subject: usb: dwc3: gadget: Stop TRB preparation after limit is reached
DWC3 gadget sets up a pool of 32 TRBs for each EP during initialization. This
means, the max TRBs that can be submitted for an EP is fixed to 32. Since the
request queue for an EP is a linked list, any number of requests can be queued
to it by the gadget layer. However, the dwc3 driver must not submit TRBs more
than the pool it has created for. This limit wasn't respected when SG was used
resulting in submitting more than the max TRBs, eventually leading to
non-transfer of the TRBs submitted over the max limit.
Root cause:
When SG is used, there are two loops iterating to prepare TRBs:
- Outer loop over the request_list
- Inner loop over the SG list
The code was missing break to get out of the outer loop.
Fixes: eeb720fb21d6 (usb: dwc3: gadget: add support for SG lists)
Cc: <stable@xxxxxxxxxxxxxxx> # v3.9+
Signed-off-by: Amit Virdi <amit.virdi@xxxxxx>
Signed-off-by: Felipe Balbi <balbi@xxxxxx>
---
drivers/usb/dwc3/gadget.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 0eec2e917994..8f65ab3a3b92 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -900,6 +900,9 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting)
if (last_one)
break;
}
+
+ if (last_one)
+ break;
} else {
dma = req->request.dma;
length = req->request.length;
--
2.2.2
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