mei: keep the device awake during reads in chunks

Long messages are read in chunks, to prevent trashing runtime pm between
the reading of the chunks we call pm_runtime_mark_last_busy() on
non-final chunk message as the next chunk of the same message will be
received immediately in the next interrupt with high probablity.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/interrupt.c

@@ -21,6 +21,7 @@
 #include <linux/fs.h>
 #include <linux/jiffies.h>
 #include <linux/slab.h>
+#include <linux/pm_runtime.h>
 
 #include <linux/mei.h>
 
@@ -147,6 +148,9 @@ int mei_cl_irq_read_msg(struct mei_cl *cl,
 		cb->read_time = jiffies;
 		cl_dbg(dev, cl, "completed read length = %lu\n", cb->buf_idx);
 		list_move_tail(&cb->list, &complete_list->list);
+	} else {
+		pm_runtime_mark_last_busy(dev->dev);
+		pm_request_autosuspend(dev->dev);
 	}
 
 out: