USB-3 does not have any link state that will avoid negotiating a connection
with a plugged-in cable but will signal the host when the cable is
unplugged.
For USB-3 we used to first set the link to Disabled, then to RxDdetect to
be able to detect cable connects or disconnects. But in RxDetect the
connected device is detected again and eventually enabled.
Instead set the link into U3 and disable remote wakeups for the device.
This is what Windows does, and what Alan Stern suggested.
Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
---
Changes since RFC-PATCH
- send port_dev as an argument
- set device state to USB_STATE_NOTATTACHED _after_ disabling remote wakup
and port disable.
---
drivers/usb/core/hub.c | 78 ++++++++++++++------------------------------------
1 file changed, 22 insertions(+), 56 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 76e80d8..d7e30f8 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -103,6 +103,7 @@
static void hub_release(struct kref *kref);
static int usb_reset_and_verify_device(struct usb_device *udev);
+static int usb_disable_remote_wakeup(struct usb_device *udev);
static inline char *portspeed(struct usb_hub *hub, int portstatus)
{
@@ -901,65 +902,30 @@ static int hub_set_port_link_state(struct usb_hub *hub, int port1,
}
/*
- * If USB 3.0 ports are placed into the Disabled state, they will no longer
- * detect any device connects or disconnects. This is generally not what the
- * USB core wants, since it expects a disabled port to produce a port status
- * change event when a new device connects.
+ * USB 3 does not have a similar link state as USB 2 that will avoid negotiating
+ * a connection with a plugged-in cable but will signal the host when the cable
+ * is unplugged.
*
- * Instead, set the link state to Disabled, wait for the link to settle into
- * that state, clear any change bits, and then put the port into the RxDetect
- * state.
+ * Instead set the link into U3 and disable remote wakeups for the device.
*/
-static int hub_usb3_port_disable(struct usb_hub *hub, int port1)
+static int hub_usb3_port_disable(struct usb_hub *hub, struct usb_port *port_dev)
{
- int ret;
- int total_time;
- u16 portchange, portstatus;
-
- if (!hub_is_superspeed(hub->hdev))
- return -EINVAL;
-
- ret = hub_port_status(hub, port1, &portstatus, &portchange);
- if (ret < 0)
- return ret;
+ struct usb_device *udev = port_dev->child;
+ int ret = 0;
- /*
- * USB controller Advanced Micro Devices, Inc. [AMD] FCH USB XHCI
- * Controller [1022:7814] will have spurious result making the following
- * usb 3.0 device hotplugging route to the 2.0 root hub and recognized
- * as high-speed device if we set the usb 3.0 port link state to
- * Disabled. Since it's already in USB_SS_PORT_LS_RX_DETECT state, we
- * check the state here to avoid the bug.
- */
- if ((portstatus & USB_PORT_STAT_LINK_STATE) ==
- USB_SS_PORT_LS_RX_DETECT) {
- dev_dbg(&hub->ports[port1 - 1]->dev,
- "Not disabling port; link state is RxDetect\n");
- return ret;
+ if (udev && udev->port_is_suspended && udev->do_remote_wakeup) {
+ ret = hub_set_port_link_state(hub, port_dev->portnum,
+ USB_SS_PORT_LS_U0);
+ if (ret)
+ goto out;
+ msleep(USB_RESUME_TIMEOUT);
+ ret = usb_disable_remote_wakeup(udev);
}
-
- ret = hub_set_port_link_state(hub, port1, USB_SS_PORT_LS_SS_DISABLED);
+out:
if (ret)
- return ret;
-
- /* Wait for the link to enter the disabled state. */
- for (total_time = 0; ; total_time += HUB_DEBOUNCE_STEP) {
- ret = hub_port_status(hub, port1, &portstatus, &portchange);
- if (ret < 0)
- return ret;
-
- if ((portstatus & USB_PORT_STAT_LINK_STATE) ==
- USB_SS_PORT_LS_SS_DISABLED)
- break;
- if (total_time >= HUB_DEBOUNCE_TIMEOUT)
- break;
- msleep(HUB_DEBOUNCE_STEP);
- }
- if (total_time >= HUB_DEBOUNCE_TIMEOUT)
- dev_warn(&hub->ports[port1 - 1]->dev,
- "Could not disable after %d ms\n", total_time);
-
- return hub_set_port_link_state(hub, port1, USB_SS_PORT_LS_RX_DETECT);
+ dev_warn(&udev->dev, "Port disable: can't disable remote wake\n");
+ return hub_set_port_link_state(hub, port_dev->portnum,
+ USB_SS_PORT_LS_U3);
}
static int hub_port_disable(struct usb_hub *hub, int port1, int set_state)
@@ -968,15 +934,15 @@ static int hub_port_disable(struct usb_hub *hub, int port1, int set_state)
struct usb_device *hdev = hub->hdev;
int ret = 0;
- if (port_dev->child && set_state)
- usb_set_device_state(port_dev->child, USB_STATE_NOTATTACHED);
if (!hub->error) {
if (hub_is_superspeed(hub->hdev))
- ret = hub_usb3_port_disable(hub, port1);
+ ret = hub_usb3_port_disable(hub, port_dev);
else
ret = usb_clear_port_feature(hdev, port1,
USB_PORT_FEAT_ENABLE);
}
+ if (port_dev->child && set_state)
+ usb_set_device_state(port_dev->child, USB_STATE_NOTATTACHED);
if (ret && ret != -ENODEV)
dev_err(&port_dev->dev, "cannot disable (err = %d)\n", ret);
return ret;
--
1.9.1
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