[PATCH 6.18 666/752] usb: dwc2: fix resume failure if dr_mode is host

Sasha Levin
2026-02-28T17:58:01Z

From: Jisheng Zhang <jszhang@kernel.org>

[ Upstream commit a52e4f2dff413b58c7200e89bb6540bd995e1269 ]

commit 13b1f8e25bfd1 ("usb: dwc2: Force mode optimizations") removed the
dwc2_force_mode(hsotg, true) in dwc2_force_dr_mode() if dr_mode is host.

But this brings a bug: the controller fails to resume back as host,
further debugging shows that the controller is resumed as peripheral.
The reason is dwc2_force_dr_mode() missed the host mode forcing, and
when resuming from s2ram, GINTSTS is 0 by default, dwc2_is_device_mode
in dwc2_resume() misreads this as the controller is in peripheral mode.

Fix the resume failure by adding back the dwc2_force_mode(hsotg, true).

Then an obvious question is: why this bug hasn't been observed and fixed
for about six years? There are two resons: most dwc2 platforms set the
dr_mode as otg; Some platforms don't have suspend & resume support yet.

Fixes: 13b1f8e25bfd1 ("usb: dwc2: Force mode optimizations")
Cc: stable <stable@kernel.org>
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Link: https://patch.msgid.link/20260129021534.10411-1-jszhang@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/dwc2/core.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c
index c3d24312db0fe..f375c5185bfe2 100644
--- a/drivers/usb/dwc2/core.c
+++ b/drivers/usb/dwc2/core.c
@@ -578,6 +578,7 @@ void dwc2_force_dr_mode(struct dwc2_hsotg *hsotg)
{
switch (hsotg->dr_mode) {
case USB_DR_MODE_HOST:
+ dwc2_force_mode(hsotg, true);
/*
* NOTE: This is required for some rockchip soc based
* platforms on their host-only dwc2.
--
2.51.0