On Thu, 02 Jun 2022, Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > 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. Fair enough. I'm not sure how useful that is going to be, though, at least not for i915. If we add a .get_edid hook, where would you bolt that? It doesn't feel right to set a .get_modes hook to a default function that goes on to call a .get_edid hook. Or what do you think? BR, Jani. > >> >> /* >> * 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 -- Jani Nikula, Intel Open Source Graphics Center