linux-kernel - [PATCH 5.4 06/27] usb: dwc3: gadget: Allow runtime suspend if UDC unbinded

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Message-Id: <20210813150523.580367784@linuxfoundation.org>
Date:   Fri, 13 Aug 2021 17:07:04 +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,
        "stable@...r.kernel.org, Wesley Cheng" <wcheng@...eaurora.org>,
        Wesley Cheng <wcheng@...eaurora.org>
Subject: [PATCH 5.4 06/27] usb: dwc3: gadget: Allow runtime suspend if UDC unbinded

From: Wesley Cheng <wcheng@...eaurora.org>

[ Upstream commit 77adb8bdf4227257e26b7ff67272678e66a0b250 ]

The DWC3 runtime suspend routine checks for the USB connected parameter to
determine if the controller can enter into a low power state.  The
connected state is only set to false after receiving a disconnect event.
However, in the case of a device initiated disconnect (i.e. UDC unbind),
the controller is halted and a disconnect event is never generated.  Set
the connected flag to false if issuing a device initiated disconnect to
allow the controller to be suspended.

Signed-off-by: Wesley Cheng <wcheng@...eaurora.org>
Link: https://lore.kernel.org/r/1609283136-22140-2-git-send-email-wcheng@codeaurora.org
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/usb/dwc3/gadget.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2018,6 +2018,17 @@ static int dwc3_gadget_pullup(struct usb
 	}
 
 	/*
+	 * Check the return value for successful resume, or error.  For a
+	 * successful resume, the DWC3 runtime PM resume routine will handle
+	 * the run stop sequence, so avoid duplicate operations here.
+	 */
+	ret = pm_runtime_get_sync(dwc->dev);
+	if (!ret || ret < 0) {
+		pm_runtime_put(dwc->dev);
+		return 0;
+	}
+
+	/*
 	 * Synchronize any pending event handling before executing the controller
 	 * halt routine.
 	 */
@@ -2055,10 +2066,12 @@ static int dwc3_gadget_pullup(struct usb
 			dwc->ev_buf->lpos = (dwc->ev_buf->lpos + count) %
 						dwc->ev_buf->length;
 		}
+		dwc->connected = false;
 	}
 
 	ret = dwc3_gadget_run_stop(dwc, is_on, false);
 	spin_unlock_irqrestore(&dwc->lock, flags);
+	pm_runtime_put(dwc->dev);
 
 	return ret;
 }