Re: [PATCH v2] usb: dwc3: Abort suspend on soft disconnect failure

On Thu, Mar 27, 2025 at 7:01 AM Thinh Nguyen Thinh.Nguyen@synopsys.com wrote:

On Mon, Mar 24, 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: c8540870af4c ("usb: dwc3: gadget: Improve dwc3_gadget_suspend()

Keep Fixes tag in a single line. I think this issue goes further back, perhaps the Fixes tag better reference here?

9f8a67b65a49 ("usb: dwc3: gadget: fix gadget suspend/resume")

Fixed! I really appreciate your patience with this and the detailed code review!

Sent out the v3 patch. https://lore.kernel.org/linux-usb/20250327133233.2566528-1-khtsai@google.com...

Thanks, Kuen-Han

Thanks, Thinh

...

and dwc3_gadget_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:

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)

2.49.0.395.g12beb8f557-goog