linux-kernel - [PATCH 1/2] usb: Prefer firmware values when determining whether a port is removable

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Date:	Wed,  8 Apr 2015 16:36:00 -0700
From:	Matthew Garrett <mjg59@...eos.com>
To:	gregkh@...uxfoundation.org
Cc:	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	Matthew Garrett <mjg59@...eos.com>
Subject: [PATCH 1/2] usb: Prefer firmware values when determining whether a port is removable

Windows appears to pay more attention to the ACPI values than any hub
configuration, so prefer the firmware's opinion on whether a port is
fixed or removable before falling back to the hub values.

Signed-off-by: Matthew Garrett <mjg59@...eos.com>
---
 drivers/usb/core/hub.c | 32 +++++++++++++++++---------------
 1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index d7c3d5a..ac33fdd 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2350,6 +2350,23 @@ static void set_usb_port_removable(struct usb_device *udev)
 
 	hub = usb_hub_to_struct_hub(udev->parent);
 
+	/*
+	 * If the platform firmware has provided information about a port,
+	 * use that to determine whether it's removable.
+	 */
+	switch (hub->ports[udev->portnum - 1]->connect_type) {
+	case USB_PORT_CONNECT_TYPE_HOT_PLUG:
+		udev->removable = USB_DEVICE_REMOVABLE;
+		return;
+	case USB_PORT_CONNECT_TYPE_HARD_WIRED:
+		udev->removable = USB_DEVICE_FIXED;
+		return;
+	}
+
+	/*
+	 * Otherwise, check whether the hub knows whether a port is removable
+	 * or not
+	 */
 	wHubCharacteristics = le16_to_cpu(hub->descriptor->wHubCharacteristics);
 
 	if (!(wHubCharacteristics & HUB_CHAR_COMPOUND))
@@ -2369,21 +2386,6 @@ static void set_usb_port_removable(struct usb_device *udev)
 	else
 		udev->removable = USB_DEVICE_FIXED;
 
-	/*
-	 * Platform firmware may have populated an alternative value for
-	 * removable.  If the parent port has a known connect_type use
-	 * that instead.
-	 */
-	switch (hub->ports[udev->portnum - 1]->connect_type) {
-	case USB_PORT_CONNECT_TYPE_HOT_PLUG:
-		udev->removable = USB_DEVICE_REMOVABLE;
-		break;
-	case USB_PORT_CONNECT_TYPE_HARD_WIRED:
-		udev->removable = USB_DEVICE_FIXED;
-		break;
-	default: /* use what was set above */
-		break;
-	}
 }
 
 /**
-- 
2.3.4

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