USB: android: Fix missing USB DISCONNECT uevent
Some userspace modules, e.g. MTP, work correctly only if
CONFIGURED uevent is preceded by DISCONNECT uevent. Hence,
explicitly send DISCONNECT uevent if missed out due to
really quick enumeration by USB Host.
Also, wait for some time before sending out CONFIGURED uevent
to give function drivers a chance to wakeup userspace threads
and notify previous disconnect.
Change-Id: I231b8de60b25a05e2316074b8694c9cbc15bb556
CRs-Fixed: 348066
Signed-off-by: Manu Gautam <mgautam@codeaurora.org>
diff --git a/drivers/usb/gadget/android.c b/drivers/usb/gadget/android.c
index ee44846..3e5c6f1 100644
--- a/drivers/usb/gadget/android.c
+++ b/drivers/usb/gadget/android.c
@@ -183,6 +183,12 @@
.bConfigurationValue = 1,
};
+enum android_device_state {
+ USB_DISCONNECTED,
+ USB_CONNECTED,
+ USB_CONFIGURED,
+};
+
static void android_work(struct work_struct *data)
{
struct android_dev *dev = container_of(data, struct android_dev, work);
@@ -191,18 +197,45 @@
char *connected[2] = { "USB_STATE=CONNECTED", NULL };
char *configured[2] = { "USB_STATE=CONFIGURED", NULL };
char **uevent_envp = NULL;
+ static enum android_device_state last_uevent, next_state;
unsigned long flags;
spin_lock_irqsave(&cdev->lock, flags);
- if (cdev->config)
+ if (cdev->config) {
uevent_envp = configured;
- else if (dev->connected != dev->sw_connected)
+ next_state = USB_CONFIGURED;
+ } else if (dev->connected != dev->sw_connected) {
uevent_envp = dev->connected ? connected : disconnected;
+ next_state = dev->connected ? USB_CONNECTED : USB_DISCONNECTED;
+ }
dev->sw_connected = dev->connected;
spin_unlock_irqrestore(&cdev->lock, flags);
if (uevent_envp) {
+ /*
+ * Some userspace modules, e.g. MTP, work correctly only if
+ * CONFIGURED uevent is preceded by DISCONNECT uevent.
+ * Check if we missed sending out a DISCONNECT uevent. This can
+ * happen if host PC resets and configures device really quick.
+ */
+ if (((uevent_envp == connected) &&
+ (last_uevent != USB_DISCONNECTED)) ||
+ ((uevent_envp == configured) &&
+ (last_uevent == USB_CONFIGURED))) {
+ pr_info("%s: sent missed DISCONNECT event\n", __func__);
+ kobject_uevent_env(&dev->dev->kobj, KOBJ_CHANGE,
+ disconnected);
+ msleep(20);
+ }
+ /*
+ * Before sending out CONFIGURED uevent give function drivers
+ * a chance to wakeup userspace threads and notify disconnect
+ */
+ if (uevent_envp == configured)
+ msleep(50);
+
kobject_uevent_env(&dev->dev->kobj, KOBJ_CHANGE, uevent_envp);
+ last_uevent = next_state;
pr_info("%s: sent uevent %s\n", __func__, uevent_envp[0]);
} else {
pr_info("%s: did not send uevent (%d %d %p)\n", __func__,