usb-msctest: Be more conservative setting GETMAXLUN quirk

Only set the GETMAXLUN quirk when it causes an error, but don't set it
when it returns 0. Since we reset the device when we set any quirk, only
set this quirk when it generates an error so umass will avoid it. When
the command works, there's no reason for umass to avoid it at all.

MFC After: 1 week
Sponsored by: Netflix

Author: bsdimp

sys/dev/usb/usb_msctest.c

@@ -741,11 +741,10 @@ usb_iface_is_cdrom(struct usb_device *udev, uint8_t iface_index)
 	return (is_cdrom);
 }
 
-static uint8_t
+static int
 usb_msc_get_max_lun(struct usb_device *udev, uint8_t iface_index)
 {
 	struct usb_device_request req;
-	usb_error_t err;
 	uint8_t buf = 0;
 
 	/* The Get Max Lun command is a class-specific request. */
@@ -756,11 +755,7 @@ usb_msc_get_max_lun(struct usb_device *udev, uint8_t iface_index)
 	req.wIndex[1] = 0;
 	USETW(req.wLength, 1);
 
-	err = usbd_do_request(udev, NULL, &req, &buf);
-	if (err)
-		buf = 0;
-
-	return (buf);
+	return usbd_do_request(udev, NULL, &req, &buf);
 }
 
 #define	USB_ADD_QUIRK(udev, any, which) do { \
@@ -803,8 +798,8 @@ usb_msc_auto_quirk(struct usb_device *udev, uint8_t iface_index,
 	usb_pause_mtx(NULL, hz);
 
 	if (usb_test_quirk(uaa, UQ_MSC_NO_GETMAXLUN) == 0 &&
-	    usb_msc_get_max_lun(udev, iface_index) == 0) {
-		DPRINTF("Device has only got one LUN.\n");
+	    usb_msc_get_max_lun(udev, iface_index) != 0) {
+		DPRINTF("Device can't handle GETMAXLUN\n");
 		USB_ADD_QUIRK(udev, any_quirk, UQ_MSC_NO_GETMAXLUN);
 	}