Re: [PATCH v2] usb: dwc3: tell xHCI that it lost its state when the core is powered off

[sashiko-bot@kernel.org]

> dwc3_suspend_common() powers the core off for system suspend
> (dwc3_core_exit()) in OTG mode (DWC3_GCTL_PRTCAP_OTG), and in host mode
> when the controller may not wake the system or needs a full re-init. The
> xHCI registers and the state saved with the Controller Save State
> command are gone then, but nothing tells xhci-plat: xhci_resume() takes
> the "state intact" path, writes the saved registers back and asks the
> controller to restore its state (CRS).
> 
> xhci-plat has a flag for exactly this, power_lost (commit 668cc6bc1178
> ("usb: host: xhci-plat: allow upper layers to signal power loss"), used
> by cdns3), but dwc3 never sets it.
> 
> On a Lenovo Y700 Gen 5 (TB323FU, SM8850; DWC3 + eUSB2 PHY) with a USB
> 2.0 hub, a USB 3 flash drive and a Billboard device attached, and USB
> wakeup disabled, s2idle then broke the host controller on resume: either
> [ ... ]
> the dwc3 core is suspended does not reset the controller.
> 
> Fixes: c4a5153e87fd ("usb: dwc3: core: Power-off core/PHYs on system_suspend in host mode")
> Fixes: f09cc79b4b33 ("usb: dwc3: add dual role support using OTG block")
> Signed-off-by: Joonhoe Kim <26rote@gmail.com>

Sashiko has reviewed this patch and found no issues.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261112141512.1840-1-26rote@gmail.com?part=1