Hubs have a flag to indicate whether a given port carries removable devices
or not. We can use this to give a hint to userspace as to the device
visibility. This is not strictly accurate in that some built-in devices
will be flagged as visible, but followup patches will make use of platform
data to make this more reliable.
Signed-off-by: Matthew Garrett <mjg@xxxxxxxxxx>
---
drivers/usb/core/hub.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 48 insertions(+), 0 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index a428aa0..e8e470e 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1838,6 +1838,46 @@ fail:
return err;
}
+/**
+ * usb_probe_device_visibility - determine a device's visibility
+ * @udev: pointer to device whose visibility should be probed
+ *
+ * Examines a hub's DeviceRemovable descriptor to determine whether a given
+ * device is externally visible or not. This is likely to flag many
+ * built-in devices as visible, but can be overridden by platform-specific
+ * data sources.
+ */
+static void usb_set_device_visibility(struct usb_device *udev)
+{
+ struct usb_device *hdev = udev->parent;
+ struct usb_hub *hub;
+ u8 port = udev->portnum;
+ u16 wHubCharacteristics;
+ bool visible = true;
+
+ if (!hdev)
+ return;
+
+ hub = hdev_to_hub(udev->parent);
+
+ wHubCharacteristics = le16_to_cpu(hub->descriptor->wHubCharacteristics);
+
+ if (!wHubCharacteristics & HUB_CHAR_COMPOUND)
+ return;
+
+ if (hub_is_superspeed(hdev)) {
+ if (hub->descriptor->u.ss.DeviceRemovable & (1 << port))
+ visible = false;
+ } else {
+ if (hub->descriptor->u.hs.DeviceRemovable[port / 8] & (1 << (port % 8)))
+ visible = false;
+ }
+
+ if (visible)
+ udev->visible = USB_DEVICE_VISIBILITY_VISIBLE;
+ else
+ udev->visible = USB_DEVICE_VISIBILITY_HIDDEN;
+}
/**
* usb_new_device - perform initial device setup (usbcore-internal)
@@ -1896,6 +1936,14 @@ int usb_new_device(struct usb_device *udev)
announce_device(udev);
device_enable_async_suspend(&udev->dev);
+
+ /* Check whether the hub marks this port as non-removable. Do
+ * it now so that platform-specific data can override it in
+ * device_add()
+ */
+ if (udev->parent)
+ usb_set_device_visibility(udev);
+
/* Register the device. The device driver is responsible
* for configuring the device and invoking the add-device
* notifier chain (used by usbfs and possibly others).
--
1.7.6.4
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