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Subject[PATCH] usb: dwc3: gadget: Fix ISO transfer performance
Date
Commit 08a36b543803 ("usb: dwc3: gadget: simplify __dwc3_gadget_ep_queue()")
caused a small change in the way ISO transfer is handled in the case
when XferInProgress event happens on Isoc EP with an active transfer.
This caused a performance degradation of 50%. e.g. using g_webcam on DUT
and luvcview on host the video frame rate dropped from 16fps to 8fps
@high-speed.

Make the ISO transfer handling equivalent to that prior to that commit
to get back the original ISO performance numbers.

Fixes: 08a36b543803 ("usb: dwc3: gadget: simplify __dwc3_gadget_ep_queue()")
Signed-off-by: Roger Quadros <rogerq@ti.com>
---
drivers/usb/dwc3/gadget.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 0d75158..8f71ccc 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1245,14 +1245,24 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, struct dwc3_request *req)
__dwc3_gadget_start_isoc(dwc, dep, cur_uf);
dep->flags &= ~DWC3_EP_PENDING_REQUEST;
}
+ return 0;
}
- return 0;
+
+ if ((dep->flags & DWC3_EP_BUSY) &&
+ !(dep->flags & DWC3_EP_MISSED_ISOC)) {
+ WARN_ON_ONCE(!dep->resource_index);
+ ret = __dwc3_gadget_kick_transfer(dep,
+ dep->resource_index);
+ }
+
+ goto out;
}

if (!dwc3_calc_trbs_left(dep))
return 0;

ret = __dwc3_gadget_kick_transfer(dep, 0);
+out:
if (ret == -EBUSY)
ret = 0;

--
2.7.4
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