From aa6812be1feb75139b9bc263915b3f1ceeb4e154 Mon Sep 17 00:00:00 2001 From: Thinh Nguyen Date: Mon, 7 Mar 2022 18:59:56 -0800 Subject: 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: Michael Grzeschik Signed-off-by: Thinh Nguyen Link: https://lore.kernel.org/r/deb8146b8e1f7f8495ef2d5647017270934cb2d8.1646708142.git.Thinh.Nguyen@synopsys.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/dwc3/gadget.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'drivers/usb/dwc3/gadget.c') diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index a0c883f19a41..eb88ef5dd16f 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -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) -- cgit v1.2.3-59-g8ed1b