Message-ID: <sashiko-outbox-206491@kernel.org>
From: sashiko-bot@kernel.org
Subject: Re: [PATCH 1/2] usb: dwc3: Tell xhci-plat when the core lost its
 state on resume
Reply-To: sashiko-reviews@lists.linux.dev
To: "Arun Iyengar" <aiyengar1990@gmail.com>
Cc: linux-usb@vger.kernel.org
In-Reply-To: <20261110-dwc3-s2idle-v1-1-2ef4cc3f8130@gmail.com>
References: <20261110-dwc3-s2idle-v1-0-2ef4cc3f8130@gmail.com>
 <20261110-dwc3-s2idle-v1-1-2ef4cc3f8130@gmail.com>
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Date: Tue, 10 Nov 2026 07:28:09 +0000
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> From: Arun Iyengar <aiyengar1990@gmail.com>
>=20
> In host mode without wakeup, dwc3_suspend_common() tears the core down
> with dwc3_core_exit() and dwc3_resume_common() initialises it again, so
> the xHCI registers are back at their reset values when xhci-plat resumes.
> xhci_resume() is not told about this: it writes the saved operational
> registers back and asks the controller to restore its internal state
> (USBCMD.CRS), which cannot work on a freshly reset core. It fails with
> USBSTS.SRE, and xhci_resume() only then falls back to a full reset:
>=20
>   xhci-hcd xhci-hcd.1.auto: xHC error in resume, USBSTS 0x401, Reinit
>=20
> xhci-plat already has a way for the glue to report this:
> xhci_plat_priv.power_lost, which cdns3 sets the same way. Set it from
> dwc3_resume_common() whenever the core was re-initialised (and clear it
> when it was kept running for wakeup), so xhci_resume() goes straight to
> the reset and re-init path.
>=20
> Signed-off-by: Arun Iyengar <aiyengar1990@gmail.com>

Sashiko has reviewed this patch and found no issues.

--=20
Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261110-dwc3-s2idl=
e-v1-0-2ef4cc3f8130@gmail.com?part=3D1