4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Lyude Paul <lyude@redhat.com>

commit dc854914999d5d52ac1b31740cb0ea8d89d0372e upstream.

Remember, ida IDs start at 0, not 1!

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Karol Herbst <redacted>
Cc: stable@vger.kernel.org
Signed-off-by: Ben Skeggs <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/nouveau/nouveau_backlight.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/nouveau/nouveau_backlight.c
+++ b/drivers/gpu/drm/nouveau/nouveau_backlight.c

@@ -116,7 +116,7 @@ nv40_backlight_init(struct drm_connector
 				       &nv40_bl_ops, &props);
 
 	if (IS_ERR(bd)) {
-		if (bl_connector.id > 0)
+		if (bl_connector.id >= 0)
 			ida_simple_remove(&bl_ida, bl_connector.id);
 		return PTR_ERR(bd);
 	}

@@ -249,7 +249,7 @@ nv50_backlight_init(struct drm_connector
 				       nv_encoder, ops, &props);
 
 	if (IS_ERR(bd)) {
-		if (bl_connector.id > 0)
+		if (bl_connector.id >= 0)
 			ida_simple_remove(&bl_ida, bl_connector.id);
 		return PTR_ERR(bd);
 	}