From aa6812be1feb75139b9bc263915b3f1ceeb4e154 Mon Sep 17 00:00:00 2001
From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Date: Mon, 7 Mar 2022 18:59:56 -0800
Subject: [PATCH] usb: dwc3: gadget: Give some time to schedule isoc
Git-commit: aa6812be1feb75139b9bc263915b3f1ceeb4e154
References: git-fixes
Patch-mainline: v5.18-rc1
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 <m.grzeschik@pengutronix.de>
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/deb8146b8e1f7f8495ef2d5647017270934cb2d8.1646708142.git.Thinh.Nguyen@synopsys.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
drivers/usb/dwc3/gadget.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
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)
--
2.35.3