[mutter] kms-impl-simple: Include mode name in error message

[Jonas Ådahl <jadahl src gnome org>]

commit 7733f8816810780ad857bce0d59ee65920e6989e
Author: Jonas Ådahl <jadahl gmail com>
Date:   Tue Jan 14 11:23:04 2020 +0100

    kms-impl-simple: Include mode name in error message
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/1007

 src/backends/native/meta-kms-impl-simple.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/src/backends/native/meta-kms-impl-simple.c b/src/backends/native/meta-kms-impl-simple.c
index cd18ce736..c4dd31d38 100644
--- a/src/backends/native/meta-kms-impl-simple.c
+++ b/src/backends/native/meta-kms-impl-simple.c
@@ -247,7 +247,8 @@ process_mode_set (MetaKmsImpl     *impl,
   if (ret != 0)
     {
       g_set_error (error, G_IO_ERROR, g_io_error_from_errno (-ret),
-                   "Failed to set mode on CRTC %u: %s",
+                   "Failed to set mode %s on CRTC %u: %s",
+                   mode_set->drm_mode ? mode_set->drm_mode->name : "off",
                    meta_kms_crtc_get_id (crtc),
                    g_strerror (-ret));
       return FALSE;