[mutter/gnome-3-32] backends: Fallback to builtin panel for devices where all heuristics fail

[Carlos Garnacho <carlosg src gnome org>]

commit f9d6627fe03f68a132501a488f73e08080018115
Author: Carlos Garnacho <carlosg gnome org>
Date:   Fri May 3 16:31:11 2019 +0200

    backends: Fallback to builtin panel for devices where all heuristics fail
    
    This is 1) relatively likely as not all touchscreens are nice enough to
    report a device size that will help us here and 2) Better than nothing if
    everything fails anyway, as it will break on multi-monitor and non-default
    monitor rotations.
    
    Closes: https://gitlab.gnome.org/GNOME/mutter/issues/581

 src/backends/meta-input-mapper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/backends/meta-input-mapper.c b/src/backends/meta-input-mapper.c
index 5227292dc..acc9b1618 100644
--- a/src/backends/meta-input-mapper.c
+++ b/src/backends/meta-input-mapper.c
@@ -381,7 +381,7 @@ guess_candidates (MetaInputMapper     *mapper,
       info->candidates[META_MATCH_SIZE] = matched_monitor;
     }
 
-  if (input->builtin)
+  if (input->builtin || best == N_OUTPUT_MATCHES)
     {
       best = MIN (best, META_MATCH_IS_BUILTIN);
       find_builtin_output (mapper, &info->candidates[META_MATCH_IS_BUILTIN]);