Not attempting to call xmodmap -pke as the service

inputremapper/system_mapping.py

@@ -90,6 +90,10 @@ class SystemMapping:
         """Get a mapping of all available names to their keycodes."""
         logger.debug("Gathering available keycodes")
         self.clear()
+
+        if not is_service():
+            # xmodmap is only available from within the login session.
+            # The service that runs via systemd can't use this.
             xmodmap_dict = {}
             try:
                 xmodmap = subprocess.check_output(
@@ -100,11 +104,13 @@ class SystemMapping:
                 xmodmap_dict = self._find_legit_mappings()
                 if len(xmodmap_dict) == 0:
                     logger.info("`xmodmap -pke` did not yield any symbol")
-        except (subprocess.CalledProcessError, FileNotFoundError):
-            # might be within a tty
-            logger.info("Optional `xmodmap` command not found. This is not critical.")
+            except FileNotFoundError:
+                logger.info(
+                    "Optional `xmodmap` command not found. This is not critical."
+                )
+            except subprocess.CalledProcessError as e:
+                logger.error('Call to `xmodmap -pke` failed with "%s"', e)
 
-        if not is_service():
             # Clients usually take care of that, don't let the service do funny things.
             # Write this stuff into the input-remapper config directory, because
             # the systemd service won't know the user sessions xmodmap.