Re: [RFC] [PATCH] usb: gadget: fix dtd dma confusion

On Mon, May 14, 2012 at 12:51:26AM +0200, Christoph Fritz wrote:

On Wed, May 09, 2012 at 02:02:22AM +0200, Christoph Fritz wrote:

quoted

Hi to All,

after a while of testing and searching I can come up with a patch
that fixes g_ether <-> iperf for fsl_udc on ARM i.MX35.

The sad part is that this kind of fix is already implemented for
marvell mv_udc driver since last year but still _not_ in the ~15
other *udc.c drivers.

See here:
daec765da767e4a6a30e1298862b28f2cae9a73f
usb: gadget: mv_udc: fix dtd dma confusion

So hereby I'm CC-ing all *udc.c maintainers to point out that this
issue maybe affects you too.


---
Subject: [PATCH] usb: gadget: fsl_udc: fix dtd dma confusion

The controller will hang when doing testings with g_ether and iperf
(tool for measuring maximum TCP and UDP bandwidth).  This patch adds a
delay to wait for controller to release dtd dma before freeing it.

Signed-off-by: Christoph Fritz <redacted>
---
 drivers/usb/gadget/fsl_udc_core.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/drivers/usb/gadget/fsl_udc_core.c b/drivers/usb/gadget/fsl_udc_core.c
index 55abfb6..fc86108 100644
--- a/drivers/usb/gadget/fsl_udc_core.c
+++ b/drivers/usb/gadget/fsl_udc_core.c

@@ -1638,6 +1638,15 @@ static int process_ep_req(struct fsl_udc *udc, int pipe,
 			status = REQ_UNCOMPLETE;
 			return status;
 		} else if (remaining_length) {
+			/* wait controller release dtd dma */
+			while ((curr_qh->curr_dtd_ptr == curr_td->td_dma)) {
+				if (curr_td->next_td_ptr ==
+						EP_QUEUE_HEAD_NEXT_TERMINATE) {
+					udelay(100);
+					break;
+				}
+				udelay(1);
+			}
 			if (direction) {
 				VDBG("Transmit dTD remaining length not zero");
 				status = -EPROTO;

-- 
1.7.2.5

 ping  -  what about this patch? Will it be applied?

RFC patches are never applied, as you are asking for comments, not for
the patch to actually be applied...

Submit it properly if you wish it to be accepted.

thanks,

greg k-h