Messages in this thread Patch in this message | | | From | Daniel Glöckner <> | Subject | [PATCH] imx_udc: don't queue more data when zlp is to be sent | Date | Thu, 28 May 2009 13:00:14 +0200 |
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When a zero-length packet has been requested and another packet is written into the fifo, the MX1 tends to send the first byte of the previous packet instead of the first byte of the current packet. The CRC is adjusted accordingly so that this packet is _not_ discarded by the host.
Waiting for the ZLPS bit to clear avoids these bad packets.
Signed-off-by: Daniel Glöckner <dg@emlix.com> --- drivers/usb/gadget/imx_udc.c | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-)
diff --git a/drivers/usb/gadget/imx_udc.c b/drivers/usb/gadget/imx_udc.c index ff7658e..642cceb 100644 --- a/drivers/usb/gadget/imx_udc.c +++ b/drivers/usb/gadget/imx_udc.c @@ -415,6 +415,13 @@ static int write_packet(struct imx_ep_struct *imx_ep, struct imx_request *req) u8 *buf; int length, count, temp; + if (unlikely(__raw_readl(imx_ep->imx_usb->base + + USB_EP_STAT(EP_NO(imx_ep))) & EPSTAT_ZLPS)) { + D_TRX(imx_ep->imx_usb->dev, "<%s> zlp still queued in EP %s\n", + __func__, imx_ep->ep.name); + return -1; + } + buf = req->req.buf + req->req.actual; prefetch(buf); -- 1.6.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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