When running a "chio return" operation using a physical source unit

rather than a voltag name, do not set the CESR_VOLTAGS flags in the
CHIOGSTATUS command requesting the current status.  As voltags are an
optional feature that must be handled as "reserved" by media changers
not implementing the feature, always setting CESR_VOLTAGS resulted in
the command being aborted with an `Invalid field in CDB', and
consequently the "chio return" failed, for media changers that do not
support voltags.

MFC after:	1 week

bin/chio/chio.c

@@ -69,7 +69,7 @@ static	const char *bits_to_string(ces_status_flags, const char *);
 
 static	void find_element(char *, uint16_t *, uint16_t *);
 static	struct changer_element_status *get_element_status
-	   (unsigned int, unsigned int);
+	   (unsigned int, unsigned int, int);
 
 static	int do_move(const char *, int, char **);
 static	int do_exchange(const char *, int, char **);
@@ -969,7 +969,8 @@ do_return(const char *cname, int argc, char **argv)
 	++argv; --argc;
 
 	/* Get the status */
-	ces = get_element_status((unsigned int)type, (unsigned int)element);
+	ces = get_element_status((unsigned int)type, (unsigned int)element,
+	    CHET_VT == type);
 
 	if (NULL == ces)
 		errx(1, "%s: null element status pointer", cname);
@@ -1004,7 +1005,7 @@ do_return(const char *cname, int argc, char **argv)
  * should free() it when done.
  */
 static struct changer_element_status *
-get_element_status(unsigned int type, unsigned int element)
+get_element_status(unsigned int type, unsigned int element, int use_voltags)
 {
 	struct changer_element_status_request cesr;
 	struct changer_element_status *ces;
@@ -1020,7 +1021,8 @@ get_element_status(unsigned int type, unsigned int element)
 	cesr.cesr_element_type = (uint16_t)type;
 	cesr.cesr_element_base = (uint16_t)element;
 	cesr.cesr_element_count = 1;		/* Only this one element */
-	cesr.cesr_flags |= CESR_VOLTAGS;	/* Grab voltags as well */
+	if (use_voltags)
+		cesr.cesr_flags |= CESR_VOLTAGS; /* Grab voltags as well */
 	cesr.cesr_element_status = ces;
 
 	if (ioctl(changer_fd, CHIOGSTATUS, (char *)&cesr) == -1) {