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Tue, 29 Sep 2026 06:03:26 -0700 (PDT) Received: from DESKTOP-NM9EKIA ([125.134.240.130]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-885e106710fsm839306b3a.17.2026.09.29.06.03.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 29 Sep 2026 06:03:26 -0700 (PDT) From: Joonhoe Kim <26rote@gmail.com> To: Thinh.Nguyen@synopsys.com, gregkh@linuxfoundation.org Cc: mathias.nyman@intel.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Joonhoe Kim <26rote@gmail.com> Subject: [PATCH] usb: dwc3: tell xHCI that it lost its state when the core is powered off Date: Tue, 29 Sep 2026 22:02:52 +0900 Message-ID: <20260929130252.869-1-26rote@gmail.com> X-Mailer: git-send-email 2.55.0.windows.5 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit In host mode, dwc3_suspend_common() powers the core off for system suspend (dwc3_core_exit()) 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 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 controller wrote to an address that was not mapped arm-smmu 15000000.iommu: Unhandled context fault: fsr=0x402, iova=0xd85e7c300, fsynr=0x3d0011, cbfrsynra=0x40, cb=13 xhci-hcd xhci-hcd.2.auto: WARNING: Host System Error usb 1-1: hub failed to enable device, error -108 or its command ring would not stop xhci-hcd xhci-hcd.2.auto: Abort failed to stop command ring: -110 xhci-hcd xhci-hcd.2.auto: xHCI host controller not responding, assume dead xhci-hcd xhci-hcd.2.auto: HC died; cleaning up usb 1-1: PM: **** DPM device timeout **** Kernel panic - not syncing: usb 1-1: unrecoverable failure With wakeup enabled (the core stays powered) the same setup survived every cycle. Remember that the core was powered off and hand it to xhci-plat as power_lost from a resume_quirk, so that xhci_resume() resets the controller and the devices are re-enumerated. Unlike a static XHCI_RESET_ON_RESUME this only applies to the resumes that follow a power-off; resumes with the core kept powered (wakeup enabled) and runtime resume keep the restore path. Same kernel and setup, 30 s RTC s2idle, wakeup disabled: without this change 1/1 cycles lost the controller, with it 3/3 cycles kept all devices. Only tested on this device. Fixes: c4a5153e87fd ("usb: dwc3: core: Power-off core/PHYs on system_suspend in host mode") Assisted-by: LLM Signed-off-by: Joonhoe Kim <26rote@gmail.com> --- host.c now includes ../host/xhci.h (for hcd_to_xhci_priv()) in place of the three xHCI headers it used, as cdns3's host.c does. drivers/usb/dwc3/core.c | 2 ++ drivers/usb/dwc3/core.h | 3 +++ drivers/usb/dwc3/host.c | 20 +++++++++++++++++--- 3 files changed, 22 insertions(+), 3 deletions(-) diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index fd5c2cd36c59..b5490b9a8474 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -2572,8 +2572,10 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) if (!PMSG_IS_AUTO(msg) && (!device_may_wakeup(dwc->dev) || dwc->needs_full_reinit)) { dwc3_core_exit(dwc); + dwc->xhci_power_lost = 1; break; } + dwc->xhci_power_lost = 0; /* Let controller to suspend HSPHY before PHY driver suspends */ if (dwc->dis_u2_susphy_quirk || diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h index 608daeb7ef10..1aa898b343e6 100644 --- a/drivers/usb/dwc3/core.h +++ b/drivers/usb/dwc3/core.h @@ -1172,6 +1172,8 @@ struct dwc3_glue_ops { * @suspended: set to track suspend event due to U3/L2. * @susphy_state: state of DWC3_GUSB2PHYCFG_SUSPHY + DWC3_GUSB3PIPECTL_SUSPHY * before PM suspend. + * @xhci_power_lost: the core was powered off for system suspend in host + * mode; xHCI must not try to restore its state on resume * @imod_interval: set the interrupt moderation interval in 250ns * increments or 0 to disable. * @max_cfg_eps: current max number of IN eps used across all USB configs. @@ -1420,6 +1422,7 @@ struct dwc3 { unsigned wakeup_configured:1; unsigned suspended:1; unsigned susphy_state:1; + unsigned xhci_power_lost:1; u16 imod_interval; diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c index c5674161b2b0..c7143a8e3e32 100644 --- a/drivers/usb/dwc3/host.c +++ b/drivers/usb/dwc3/host.c @@ -14,9 +14,7 @@ #include #include -#include "../host/xhci-port.h" -#include "../host/xhci-ext-caps.h" -#include "../host/xhci-caps.h" +#include "../host/xhci.h" #include "../host/xhci-plat.h" #include "core.h" @@ -78,7 +76,23 @@ static void dwc3_xhci_plat_start(struct usb_hcd *hcd) dwc3_enable_susphy(dwc, true); } +/* + * dwc3_suspend_common() powers the core off for system suspend in host mode + * when the controller may not wake the system. The xHCI registers and its + * saved internal state are gone then: tell xhci-plat, so that xhci_resume() + * resets the controller instead of restoring registers and asking it to + * restore a state it no longer has. + */ +static int dwc3_xhci_resume_quirk(struct usb_hcd *hcd) +{ + struct dwc3 *dwc = dev_get_drvdata(hcd->self.controller->parent); + + hcd_to_xhci_priv(hcd)->power_lost = dwc->xhci_power_lost; + return 0; +} + static const struct xhci_plat_priv dwc3_xhci_plat_quirk = { + .resume_quirk = dwc3_xhci_resume_quirk, .plat_start = dwc3_xhci_plat_start, }; base-commit: 6375e61c01e93e35ee7acd336a689ac1fae4b509 -- 2.43.0