Wait for device to disappear after reboot-bootloader.
(Linux only for now) With fastboot reading serial numbers from sysfs, it had
become possible for a fastboot command issued immediately after rebooting
the bootloader to fail, because sysfs still thought the device was online.
To prevent this, after reboot-bootloader we wait for the device to disconnect.
Also made usb_read and usb_write fail immediately if the descriptor has been
closed; this prevents an incorrect error message ("Bad file descriptor")
when errors from fb_getvar are ignored (e.g., by fb_format_supported).
Also removed unused fd param from filter_usb_device, and simplified logic
in usb_write by using do/while instead of a special case for len == 0.
Change-Id: I799b857eab411fd8ad25f5777fc61c685152ea86
diff --git a/fastboot/usb.h b/fastboot/usb.h
index d504ee2..17cf0a9 100644
--- a/fastboot/usb.h
+++ b/fastboot/usb.h
@@ -62,6 +62,6 @@
int usb_close(usb_handle *h);
int usb_read(usb_handle *h, void *_data, int len);
int usb_write(usb_handle *h, const void *_data, int len);
-
+int usb_wait_for_disconnect(usb_handle *h);
#endif