Commit aa6812be authored by Thinh Nguyen's avatar Thinh Nguyen Committed by Greg Kroah-Hartman
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usb: dwc3: gadget: Give some time to schedule isoc 

Currently the driver will schedule isoc transfers immediately on the
next interval, which is quite aggressive when the interval is 125us.
There's report that some platforms may need more time to process the
transfer, otherwise the controller may miss the first interval. Let's
keep it simple and give the controller at least 500us to schedule the
isoc transfer.

Link: https://lore.kernel.org/linux-usb/20220302143539.GI11577@pengutronix.de/


Tested-by: default avatarMichael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: default avatarThinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/deb8146b8e1f7f8495ef2d5647017270934cb2d8.1646708142.git.Thinh.Nguyen@synopsys.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 62b20e6e

drivers/usb/dwc3/gadget.c

+7 −1
Original line number Diff line number Diff line
@@ -1830,7 +1830,13 @@ static int __dwc3_gadget_start_isoc(struct dwc3_ep *dep) 
	}



	for (i = 0; i < DWC3_ISOC_MAX_RETRIES; i++) {

		dep->frame_number = DWC3_ALIGN_FRAME(dep, i + 1);

		int future_interval = i + 1;



		/* Give the controller at least 500us to schedule transfers */

		if (desc->bInterval < 3)

			future_interval += 3 - desc->bInterval;



		dep->frame_number = DWC3_ALIGN_FRAME(dep, future_interval);



		ret = __dwc3_gadget_kick_transfer(dep);

		if (ret != -EAGAIN)