linux-kernel - [PATCH] xhci: Remove CONFIG_USB_DEFAULT_PERSIST to prevent xHCI from runtime suspending

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Message-Id: <20211119092628.677935-1-kai.heng.feng@canonical.com>
Date:   Fri, 19 Nov 2021 17:26:28 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     mathias.nyman@...el.com
Cc:     Kai-Heng Feng <kai.heng.feng@...onical.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org (open list:USB XHCI DRIVER),
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH] xhci: Remove CONFIG_USB_DEFAULT_PERSIST to prevent xHCI from runtime suspending

When the xHCI is quirked with XHCI_RESET_ON_RESUME, runtime resume
routine also resets the controller.

This is bad for USB drivers without reset_resume callback, because
there's no subsequent call of usb_dev_complete() ->
usb_resume_complete() to force rebinding the driver to the device. For
instance, btusb device stops working after xHCI controller is runtime
resumed, if the controlled is quirked with XHCI_RESET_ON_RESUME.

So always take XHCI_RESET_ON_RESUME into account to solve the issue.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
---
 drivers/usb/host/xhci.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 902f410874e8e..af92a9f8ed670 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3934,7 +3934,6 @@ static void xhci_free_dev(struct usb_hcd *hcd, struct usb_device *udev)
 	struct xhci_slot_ctx *slot_ctx;
 	int i, ret;
 
-#ifndef CONFIG_USB_DEFAULT_PERSIST
 	/*
 	 * We called pm_runtime_get_noresume when the device was attached.
 	 * Decrement the counter here to allow controller to runtime suspend
@@ -3942,7 +3941,6 @@ static void xhci_free_dev(struct usb_hcd *hcd, struct usb_device *udev)
 	 */
 	if (xhci->quirks & XHCI_RESET_ON_RESUME)
 		pm_runtime_put_noidle(hcd->self.controller);
-#endif
 
 	ret = xhci_check_args(hcd, udev, NULL, 0, true, __func__);
 	/* If the host is halted due to driver unload, we still need to free the
@@ -4094,14 +4092,12 @@ int xhci_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev)
 
 	xhci_debugfs_create_slot(xhci, slot_id);
 
-#ifndef CONFIG_USB_DEFAULT_PERSIST
 	/*
 	 * If resetting upon resume, we can't put the controller into runtime
 	 * suspend if there is a device attached.
 	 */
 	if (xhci->quirks & XHCI_RESET_ON_RESUME)
 		pm_runtime_get_noresume(hcd->self.controller);
-#endif
 
 	/* Is this a LS or FS device under a HS hub? */
 	/* Hub or peripherial? */
-- 
2.32.0