linux-kernel - [PATCH 5.10 012/129] xhci: increase usb U3 -> U0 link resume timeout from 100ms to 500ms

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Date:   Wed,  4 May 2022 18:43:24 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Mathias Nyman <mathias.nyman@...ux.intel.com>
Subject: [PATCH 5.10 012/129] xhci: increase usb U3 -> U0 link resume timeout from 100ms to 500ms

From: Mathias Nyman <mathias.nyman@...ux.intel.com>

commit 33597f0c48be0836854d43c577e35c8f8a765a7d upstream.

The first U3 wake signal by the host may be lost if the USB 3 connection is
tunneled over USB4, with a runtime suspended USB4 host, and firmware
implemented connection manager.

Specs state the host must wait 100ms (tU3WakeupRetryDelay) before
resending a U3 wake signal if device doesn't respond, leading to U3 -> U0
link transition times around 270ms in the tunneled case.

Fixes: 0200b9f790b0 ("xhci: Wait until link state trainsits to U0 after setting USB_SS_PORT_LS_U0")
Cc: stable@...r.kernel.org
Signed-off-by: Mathias Nyman <mathias.nyman@...ux.intel.com>
Link: https://lore.kernel.org/r/20220408134823.2527272-4-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/usb/host/xhci-hub.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -1348,7 +1348,7 @@ int xhci_hub_control(struct usb_hcd *hcd
 				}
 				spin_unlock_irqrestore(&xhci->lock, flags);
 				if (!wait_for_completion_timeout(&bus_state->u3exit_done[wIndex],
-								 msecs_to_jiffies(100)))
+								 msecs_to_jiffies(500)))
 					xhci_dbg(xhci, "missing U0 port change event for port %d-%d\n",
 						 hcd->self.busnum, wIndex + 1);
 				spin_lock_irqsave(&xhci->lock, flags);