usb: Improve companion configuration error messages

The previous commit broke the additional messages explaining the error
messages.  Improve the error messages, so they don't need explaining
so much.  Helps QMP users as well, unlike additional explanations.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/usb/bus.c

@@ -374,16 +374,14 @@ void usb_register_companion(const char *masterbus, USBPort *ports[],
         }
     }
 
-    if (!bus || !bus->ops->register_companion) {
-        error_set(errp, QERR_INVALID_PARAMETER_VALUE, "masterbus",
-                  "an USB masterbus");
-#if 0 /* conversion from qerror_report() to error_set() broke this: */
-        if (bus) {
-            error_printf_unless_qmp(
-                "USB bus '%s' does not allow companion controllers\n",
-                masterbus);
-        }
-#endif
+    if (!bus) {
+        error_setg(errp, "USB bus '%s' not found", masterbus);
+        return;
+    }
+    if (!bus->ops->register_companion) {
+        error_setg(errp, "Can't use USB bus '%s' as masterbus,"
+                   " it doesn't support companion controllers",
+                   masterbus);
         return;
     }
 

hw/usb/hcd-ehci.c

@@ -777,26 +777,17 @@ static void ehci_register_companion(USBBus *bus, USBPort *ports[],
     uint32_t i;
 
     if (firstport + portcount > NB_PORTS) {
-        error_set(errp, QERR_INVALID_PARAMETER_VALUE, "firstport",
-                  "firstport on masterbus");
-#if 0 /* conversion from qerror_report() to error_set() broke this: */
-        error_printf_unless_qmp(
-            "firstport value of %u makes companion take ports %u - %u, which "
-            "is outside of the valid range of 0 - %u\n", firstport, firstport,
-            firstport + portcount - 1, NB_PORTS - 1);
-#endif
+        error_setg(errp, "firstport must be between 0 and %u",
+                   NB_PORTS - portcount);
         return;
     }
 
     for (i = 0; i < portcount; i++) {
         if (s->companion_ports[firstport + i]) {
-            error_set(errp, QERR_INVALID_PARAMETER_VALUE, "masterbus",
-                      "an USB masterbus");
-#if 0 /* conversion from qerror_report() to error_set() broke this: */
-            error_printf_unless_qmp(
-                "port %u on masterbus %s already has a companion assigned\n",
-                firstport + i, bus->qbus.name);
-#endif
+            error_setg(errp, "firstport %u asks for ports %u-%u,"
+                       " but port %u has a companion assigned already",
+                       firstport, firstport, firstport + portcount - 1,
+                       firstport + i);
             return;
         }
     }