From 8caccd2eac33725ea2d9015ec44fff8f55d31920 Mon Sep 17 00:00:00 2001 From: Roy Luo Date: Thu, 22 May 2025 19:09:11 +0000 Subject: [PATCH] usb: xhci: Skip xhci_reset in xhci_resume if xhci is being removed commit 3eff494f6e17abf932699483f133a708ac0355dc upstream. xhci_reset() currently returns -ENODEV if XHCI_STATE_REMOVING is set, without completing the xhci handshake, unless the reset completes exceptionally quickly. This behavior causes a regression on Synopsys DWC3 USB controllers with dual-role capabilities. Specifically, when a DWC3 controller exits host mode and removes xhci while a reset is still in progress, and then attempts to configure its hardware for device mode, the ongoing, incomplete reset leads to critical register access issues. All register reads return zero, not just within the xHCI register space (which might be expected during a reset), but across the entire DWC3 IP block. This patch addresses the issue by preventing xhci_reset() from being called in xhci_resume() and bailing out early in the reinit flow when XHCI_STATE_REMOVING is set. Cc: stable Fixes: 6ccb83d6c497 ("usb: xhci: Implement xhci_handshake_check_state() helper") Suggested-by: Mathias Nyman Signed-off-by: Roy Luo Link: https://lore.kernel.org/r/20250522190912.457583-2-royluo@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 799941b6ad6c..434bed36557a 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -1094,7 +1094,10 @@ int xhci_resume(struct xhci_hcd *xhci, pm_message_t msg) xhci_dbg(xhci, "Stop HCD\n"); xhci_halt(xhci); xhci_zero_64b_regs(xhci); - retval = xhci_reset(xhci, XHCI_RESET_LONG_USEC); + if (xhci->xhc_state & XHCI_STATE_REMOVING) + retval = -ENODEV; + else + retval = xhci_reset(xhci, XHCI_RESET_LONG_USEC); spin_unlock_irq(&xhci->lock); if (retval) return retval;