Re: [PATCH v3] usb: dwc3: Abort suspend on soft disconnect failure

On Thu, Mar 27, 2025, Kuen-Han Tsai wrote:

When dwc3_gadget_soft_disconnect() fails, dwc3_suspend_common() keeps going with the suspend, resulting in a period where the power domain is off, but the gadget driver remains connected. Within this time frame, invoking vbus_event_work() will cause an error as it attempts to access DWC3 registers for endpoint disabling after the power domain has been completely shut down.

Abort the suspend sequence when dwc3_gadget_suspend() cannot halt the controller and proceeds with a soft connect.

Fixes: 9f8a67b65a49 ("usb: dwc3: gadget: fix gadget suspend/resume") CC: stable@vger.kernel.org Signed-off-by: Kuen-Han Tsai khtsai@google.com

---

Kernel panic - not syncing: Asynchronous SError Interrupt Workqueue: events vbus_event_work Call trace: dump_backtrace+0xf4/0x118 show_stack+0x18/0x24 dump_stack_lvl+0x60/0x7c dump_stack+0x18/0x3c panic+0x16c/0x390 nmi_panic+0xa4/0xa8 arm64_serror_panic+0x6c/0x94 do_serror+0xc4/0xd0 el1h_64_error_handler+0x34/0x48 el1h_64_error+0x68/0x6c readl+0x4c/0x8c __dwc3_gadget_ep_disable+0x48/0x230 dwc3_gadget_ep_disable+0x50/0xc0 usb_ep_disable+0x44/0xe4 ffs_func_eps_disable+0x64/0xc8 ffs_func_set_alt+0x74/0x368 ffs_func_disable+0x18/0x28 composite_disconnect+0x90/0xec configfs_composite_disconnect+0x64/0x88 usb_gadget_disconnect_locked+0xc0/0x168 vbus_event_work+0x3c/0x58 process_one_work+0x1e4/0x43c worker_thread+0x25c/0x430 kthread+0x104/0x1d4 ret_from_fork+0x10/0x20

---

Changelog:

v3:

• change the Fixes tag

v2:

• move declarations in separate lines
• add the Fixes tag

---

drivers/usb/dwc3/core.c | 9 +++++++-- drivers/usb/dwc3/gadget.c | 22 +++++++++------------- 2 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index 66a08b527165..1cf1996ae1fb 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -2388,6 +2388,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) { u32 reg; int i;

• int ret;

  if (!pm_runtime_suspended(dwc->dev) && !PMSG_IS_AUTO(msg)) { dwc->susphy_state = (dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0)) &

@@ -2406,7 +2407,9 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) case DWC3_GCTL_PRTCAP_DEVICE: if (pm_runtime_suspended(dwc->dev)) break;

• dwc3_gadget_suspend(dwc);
  

• ret = dwc3_gadget_suspend(dwc);
  

• if (ret)
  

• 	return ret
  

  synchronize_irq(dwc->irq_gadget); dwc3_core_exit(dwc); break;

@@ -2441,7 +2444,9 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) break;

if (dwc->current_otg_role == DWC3_OTG_ROLE_DEVICE) {

• 	dwc3_gadget_suspend(dwc);
  

• 	ret = dwc3_gadget_suspend(dwc);
  

• 	if (ret)
  

• 		return ret;
  synchronize_irq(dwc->irq_gadget);
  

  }

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 89a4dc8ebf94..316c1589618e 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -4776,26 +4776,22 @@ int dwc3_gadget_suspend(struct dwc3 *dwc) int ret;

ret = dwc3_gadget_soft_disconnect(dwc);

• if (ret)

• goto err;
  

• spin_lock_irqsave(&dwc->lock, flags);
• if (dwc->gadget_driver)

• dwc3_disconnect_gadget(dwc);
  

• spin_unlock_irqrestore(&dwc->lock, flags);
• return 0;

-err: /* * Attempt to reset the controller's state. Likely no * communication can be established until the host * performs a port reset. */

• if (dwc->softconnect)

• if (ret && dwc->softconnect) { dwc3_gadget_soft_connect(dwc);

• return ret;
  

• }

• return ret;

• spin_lock_irqsave(&dwc->lock, flags);
• if (dwc->gadget_driver)

• dwc3_disconnect_gadget(dwc);
  

• spin_unlock_irqrestore(&dwc->lock, flags);
• return 0;

}

int dwc3_gadget_resume(struct dwc3 *dwc)

2.49.0.472.ge94155a9ec-goog

Acked-by: Thinh Nguyen Thinh.Nguyen@synopsys.com

THanks, Thinh