When a display controller driver uses DRM_BRIDGE_ATTACH_NO_CONNECTOR, tc358767 will behave properly and skip the creation of the connector.
However, tc_get_display_props(), which is used to find out about the DP monitor and link, is only called from two places: .atomic_enable() and tc_connector_get_modes(). The latter is only used when tc358767 creates its own connector, i.e. when DRM_BRIDGE_ATTACH_NO_CONNECTOR is _not_ set. Thus, the driver never finds out the link properties before get_edid() is called. With num_lanes of 0 and link_rate of 0 there are not many valid modes... Fix this by adding tc_get_display_props() call at the beginning of get_edid(), so that we have up to date information before looking at the modes. Reported-by: Jan Kiszka <jan.kis...@siemens.com> Closes: https://lore.kernel.org/all/24282420-b4dd-45b3-bb1c-fc37fe4a8...@siemens.com/ Fixes: de5e6c027ae6 ("drm/bridge: tc358767: add drm_panel_bridge support") Reviewed-by: Aradhya Bhatia <a-bhat...@ti.com> Tested-by: Jan Kiszka <jan.kis...@siemens.com> Signed-off-by: Tomi Valkeinen <tomi.valkei...@ideasonboard.com> --- drivers/gpu/drm/bridge/tc358767.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c index 89a0d804270a..5aafbdf423c6 100644 --- a/drivers/gpu/drm/bridge/tc358767.c +++ b/drivers/gpu/drm/bridge/tc358767.c @@ -1579,6 +1579,13 @@ static struct edid *tc_get_edid(struct drm_bridge *bridge, struct drm_connector *connector) { struct tc_data *tc = bridge_to_tc(bridge); + int ret; + + ret = tc_get_display_props(tc); + if (ret < 0) { + dev_err(tc->dev, "failed to read display props: %d\n", ret); + return 0; + } return drm_get_edid(connector, &tc->aux.ddc); } -- 2.34.1
