On Tue, May 24, 2022 at 01:39:28PM +0300, Jani Nikula wrote:
> Add default action when .get_modes() not set. This also defines what a
> .get_modes() hook should do.
>
> Cc: David Airlie <airlied@xxxxxxxx>
> Cc: Daniel Vetter <daniel@xxxxxxxx>
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> ---
> drivers/gpu/drm/drm_probe_helper.c | 14 +++++++++++++-
> include/drm/drm_modeset_helper_vtables.h | 4 ++++
> 2 files changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
> index 836bcd5b4cb6..9df17f0ae225 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -360,7 +360,19 @@ static int drm_helper_probe_get_modes(struct drm_connector *connector)
> connector->helper_private;
> int count;
>
> - count = connector_funcs->get_modes(connector);
> + if (connector_funcs->get_modes) {
> + count = connector_funcs->get_modes(connector);
> + } else {
> + const struct drm_edid *drm_edid;
> +
> + /* Note: This requires connector->ddc is set */
> + drm_edid = drm_edid_read(connector);
> +
> + /* Update modes etc. from the EDID */
> + count = drm_edid_connector_update(connector, drm_edid);
> +
> + drm_edid_free(drm_edid);
> + }
Not really a huge fan of this automagic fallback. I think I'd prefer
to keep it mandatory and just provide this as a helper for drivers to
plug into the right spot. Otherwise I'm sure I'll forget how this works
and then I'll be confused when I see a connector withput any apparent
.get_modes() implementation.
>
> /*
> * Fallback for when DDC probe failed in drm_get_edid() and thus skipped
> diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
> index fafa70ac1337..b4402bc64e57 100644
> --- a/include/drm/drm_modeset_helper_vtables.h
> +++ b/include/drm/drm_modeset_helper_vtables.h
> @@ -894,6 +894,10 @@ struct drm_connector_helper_funcs {
> * libraries always call this with the &drm_mode_config.connection_mutex
> * held. Because of this it's safe to inspect &drm_connector->state.
> *
> + * This callback is optional. By default, it reads the EDID using
> + * drm_edid_read() and updates the connector display info, modes, and
> + * properties using drm_edid_connector_update().
> + *
> * RETURNS:
> *
> * The number of modes added by calling drm_mode_probed_add().
> --
> 2.30.2
--
Ville Syrjälä
Intel
