linux-kernel - [PATCH] usb: host: xhci: Do not re-initialize the XHCI HC if being removed

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Date:   Mon, 22 May 2023 18:53:54 -0700
From:   Wesley Cheng <quic_wcheng@...cinc.com>
To:     <mathias.nyman@...el.com>, <gregkh@...uxfoundation.org>
CC:     <linux-kernel@...r.kernel.org>, <linux-usb@...r.kernel.org>,
        <quic_jackp@...cinc.com>, Wesley Cheng <quic_wcheng@...cinc.com>
Subject: [PATCH] usb: host: xhci: Do not re-initialize the XHCI HC if being removed

During XHCI resume, if there was a host controller error detected the
routine will attempt to re-initialize the XHCI HC, so that it can return
back to an operational state.  If the XHCI host controller is being
removed, this sequence would be already handled within the XHCI halt path,
leading to a duplicate set of reg ops/calls.  In addition, since the XHCI
bus is being removed, the overhead added in restarting the HCD is
unnecessary.  Check for the XHC state before setting the reinit_xhc
parameter, which is responsible for triggering the restart.

Signed-off-by: Wesley Cheng <quic_wcheng@...cinc.com>
---
 drivers/usb/host/xhci.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index b81313ffeb76..2017ed3ae4a7 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -1028,7 +1028,8 @@ int xhci_resume(struct xhci_hcd *xhci, pm_message_t msg)
 	temp = readl(&xhci->op_regs->status);

 	/* re-initialize the HC on Restore Error, or Host Controller Error */
-	if (temp & (STS_SRE | STS_HCE)) {
+	if ((temp & (STS_SRE | STS_HCE)) &&
+		!(xhci->xhc_state & XHCI_STATE_REMOVING)) {
 		reinit_xhc = true;
 		if (!xhci->broken_suspend)
 			xhci_warn(xhci, "xHC error in resume, USBSTS 0x%x, Reinit\n", temp);