+ /* If an HD_RECEIVEATDATA_ACK message remains unhandled
+ * because of an error, the base never sends another one.
+ * The response channel is thus effectively blocked.
+ * Closing and reopening the AT channel does *not* clear
+ * this condition.
+ * As a stopgap measure, submit a zero-length AT read
+ * before closing the AT channel. This has the undocumented
+ * effect of triggering a new HD_RECEIVEATDATA_ACK message
+ * from the base if necessary.
+ * The subsequent AT channel close then discards any pending
+ * messages.
+ */
+ spin_lock_irqsave(&cs->lock, flags);
+ if (!(cs->hw.bas->basstate & BS_ATRDPEND)) {
+ kfree(cs->hw.bas->rcvbuf);
+ cs->hw.bas->rcvbuf = NULL;
+ cs->hw.bas->rcvbuf_size = 0;
+ cs->hw.bas->retry_cmd_in = 0;
+ atread_submit(cs, 0);
+ }
+ spin_unlock_irqrestore(&cs->lock, flags);
+