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[v2,1/5] usb: dwc3: gadget: start requests as soon as they come

Message ID 1442344568-1820-2-git-send-email-balbi@ti.com
State Accepted
Commit 1d6a39186b37b6f5097f9cdee8fcbfc24d231428
Headers show

Commit Message

Felipe Balbi Sept. 15, 2015, 7:16 p.m. UTC 
In an attempt to make dwc3 slightly faster, let's
start usb_requests as soon as they come as that will
let us avoid a XFER_NOT_READY event and save a little
bit of time.

Signed-off-by: Felipe Balbi <balbi@ti.com>
---
 drivers/usb/dwc3/gadget.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
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Patch

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 1ea565f307e4..d28dc6df4e55 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1072,6 +1072,22 @@  static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
 	list_add_tail(&req->list, &dep->request_list);
 
 	/*
+	 * If there are no pending requests and the endpoint isn't already
+	 * busy, we will just start the request straight away.
+	 *
+	 * This will save one IRQ (XFER_NOT_READY) and possibly make it a
+	 * little bit faster.
+	 */
+	if (!usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
+			!(dep->flags & DWC3_EP_BUSY)) {
+		ret = __dwc3_gadget_kick_transfer(dep, 0, true);
+		if (ret && ret != -EBUSY)
+			dev_dbg(dwc->dev, "%s: failed to kick transfers\n",
+					dep->name);
+		return ret;
+	}
+
+	/*
 	 * There are a few special cases:
 	 *
 	 * 1. XferNotReady with empty list of requests. We need to kick the