home-assistant/core · error · ServiceValidationError

unsupported_source

unsupported_source

Error message

Unsupported source: {source}.

What it means

ServiceValidationError with key 'unsupported_source' from arcam_fmj async_select_source: the requested source name is not a member of the SourceCodes enum in the arcam-fmj library, so it cannot be mapped to a command for the AVR.

Source

Thrown at homeassistant/components/arcam_fmj/media_player.py:94

        if power is None:
            return None
        return MediaPlayerState.ON if power else MediaPlayerState.OFF

    @convert_exception
    @override
    async def async_mute_volume(self, mute: bool) -> None:
        """Send mute command."""
        await self._state.set_mute(mute)
        self.async_write_ha_state()

    @convert_exception
    @override
    async def async_select_source(self, source: str) -> None:
        """Select a specific source."""
        try:
            value = SourceCodes[source]
        except KeyError as exception:
            raise ServiceValidationError(
                translation_domain=DOMAIN,
                translation_key="unsupported_source",
                translation_placeholders={"source": source},
            ) from exception

        await self._state.set_source(value)
        self.async_write_ha_state()

    @convert_exception
    @override
    async def async_select_sound_mode(self, sound_mode: str) -> None:
        """Select a specific source."""
        try:
            await self._state.set_decode_mode(sound_mode)
        except (KeyError, ValueError) as exception:
            raise ServiceValidationError(
                translation_domain=DOMAIN,
                translation_key="unsupported_sound_mode",

View on GitHub (pinned to 58a3fdb3ea)

Solutions

1. Call the media player's source_list / browse sources in Developer Tools to see valid names and use exactly those.
2. Fix the typo/casing in the automation or script that invokes select_source.
3. Update the arcam-fmj library if your model's source codes were added after your installed version.

Example fix

// before
action:
  - service: media_player.select_source
    target: {entity_id: media_player.arcam
    data: {source: Tv
// after
action:
  - service: media_player.select_source
    target: {entity_id: media_player.arcam
    data: {source: TV}

from arcam_fmj.source_codes import SourceCodes  # or the library's enum module

def is_valid_source(source: str) -> bool:
    return source in SourceCodes.__members__

Catch KeyError on SourceCodes[source] and raise ServiceValidationError with translation_placeholders={'source': source} (integration pattern) so the UI shows which value failed.

When it happens

Trigger: media_player.select_source is called with a string that is not a valid SourceCodes key (KeyError on SourceCodes[source]); e.g. a source name from a template/script typo or one that exists on a different AVR generation.

Common situations: Hardcoded source names in scripts/automations that drift from the device's actual source list; copied YAML between different Arcam models; case-sensitive mismatch ('TV' vs 'tv').

Related errors

• unsupported_sound_mode
• unsupported_media
• connection_failed
• Media not found: {media_content_type} / {media_content_id}
• end_time_before_start_time

AI-assisted analysis of home-assistant/core@58a3fdb3ea (2026-08-14). Data as JSON: /api/errors/eb60eb5eaf608ca6. Report an issue: GitHub.