Jisheng Zhang f5da4c24aa usb: dwc2: fix resume failure if dr_mode is host
[ Upstream commit a52e4f2dff ]

commit 13b1f8e25b ("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: 13b1f8e25b ("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>
2026-03-04 07:21:15 -05:00
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