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From:   Kai-Heng Feng <kai.heng.feng@canonical.com>
To:     mathias.nyman@intel.com
Cc:     gregkh@linuxfoundation.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Kai-Heng Feng <kai.heng.feng@canonical.com>
Subject: [PATCH v2] xhci: Fix front USB ports on ASUS PRIME B350M-A
Date:   Tue, 20 Feb 2018 03:06:21 +0800
Message-Id: <20180219190621.6632-1-kai.heng.feng@canonical.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

When a USB device gets plugged on ASUS PRIME B350M-A's front ports, the
xHC stops working:
[  549.114587] xhci_hcd 0000:02:00.0: WARN: xHC CMD_RUN timeout
[  549.114608] suspend_common(): xhci_pci_suspend+0x0/0xc0 returns -110
[  549.114638] xhci_hcd 0000:02:00.0: can't suspend (hcd_pci_runtime_suspend returned -110)

Delay before running xHC command CMD_RUN can workaround the issue.

Use a new quirk to make the delay only targets to the affected xHC.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
v2: Instead of doing xHC reset and disabling D3cold, a simple delay can
workaround the issue. Now both high-speed and super-speed devices work
fine with the v2 quirk.

 drivers/usb/host/xhci-pci.c | 3 +++
 drivers/usb/host/xhci.c     | 3 +++
 drivers/usb/host/xhci.h     | 1 +
 3 files changed, 7 insertions(+)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 6c79037876db..9a820b3cae56 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -122,6 +122,9 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
 	if (pdev->vendor == PCI_VENDOR_ID_AMD && usb_amd_find_chipset_info())
 		xhci->quirks |= XHCI_AMD_PLL_FIX;
 
+	if (pdev->vendor == PCI_VENDOR_ID_AMD && pdev->device == 0x43bb)
+		xhci->quirks |= XHCI_SUSPEND_DELAY;
+
 	if (pdev->vendor == PCI_VENDOR_ID_AMD)
 		xhci->quirks |= XHCI_TRUST_TX_LENGTH;
 
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 1eeb3396300f..d554bbd694d3 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -878,6 +878,9 @@ int xhci_suspend(struct xhci_hcd *xhci, bool do_wakeup)
 	clear_bit(HCD_FLAG_POLL_RH, &xhci->shared_hcd->flags);
 	del_timer_sync(&xhci->shared_hcd->rh_timer);
 
+	if (xhci->quirks & XHCI_SUSPEND_DELAY)
+		usleep_range(1000, 1500);
+
 	spin_lock_irq(&xhci->lock);
 	clear_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
 	clear_bit(HCD_FLAG_HW_ACCESSIBLE, &xhci->shared_hcd->flags);
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 96099a245c69..6f1f52f3cb40 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1825,6 +1825,7 @@ struct xhci_hcd {
 /* Reserved. It was XHCI_U2_DISABLE_WAKE */
 #define XHCI_ASMEDIA_MODIFY_FLOWCONTROL	(1 << 28)
 #define XHCI_HW_LPM_DISABLE	(1 << 29)
+#define XHCI_SUSPEND_DELAY	(1 << 30)
 
 	unsigned int		num_active_eps;
 	unsigned int		limit_active_eps;
-- 
2.15.1