[PATCH 5/5] xhci: Give USB2 ports time to enter U3 in bus suspend

From: Mathias Nyman <mathias.nyman@linux.intel.com>
To: <gregkh@linuxfoundation.org>
Cc: <linux-usb@vger.kernel.org>, Li Jun <jun.li@nxp.com>,
	stable@vger.kernel.org,
	Mathias Nyman <mathias.nyman@linux.intel.com>
Subject: [PATCH 5/5] xhci: Give USB2 ports time to enter U3 in bus suspend
Date: Tue,  8 Dec 2020 11:29:12 +0200	[thread overview]
Message-ID: <20201208092912.1773650-6-mathias.nyman@linux.intel.com> (raw)
In-Reply-To: <20201208092912.1773650-1-mathias.nyman@linux.intel.com>

From: Li Jun <jun.li@nxp.com>

If a USB2 device wakeup is not enabled/supported the link state may
still be in U0 in xhci_bus_suspend(), where it's then manually put
to suspended U3 state.

Just as with selective suspend the device needs time to enter U3
suspend before continuing with further suspend operations
(e.g. system suspend), otherwise we may enter system suspend with link
state in U0.

[commit message rewording -Mathias]
Cc: <stable@vger.kernel.org>
Signed-off-by: Li Jun <jun.li@nxp.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
---
 drivers/usb/host/xhci-hub.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index c799ca5361d4..74c497fd3476 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -1712,6 +1712,10 @@ int xhci_bus_suspend(struct usb_hcd *hcd)
 	hcd->state = HC_STATE_SUSPENDED;
 	bus_state->next_statechange = jiffies + msecs_to_jiffies(10);
 	spin_unlock_irqrestore(&xhci->lock, flags);
+
+	if (bus_state->bus_suspended)
+		usleep_range(5000, 10000);
+
 	return 0;
 }
 
-- 
2.25.1

