| Message ID | 20231031-tc358767-v1-2-392081ad9f4b@ideasonboard.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/bridge: tc358767: Fix DRM_BRIDGE_ATTACH_NO_CONNECTOR case | expand |
On 31-Oct-23 18:56, Tomi Valkeinen wrote: > 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_connector_get_modes() 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.kiszka@siemens.com> > Closes: https://lore.kernel.org/all/24282420-b4dd-45b3-bb1c-fc37fe4a8205@siemens.com/ > Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> > --- Thank you, Tomi, for quickly debugging this! Reviewed-by: Aradhya Bhatia <a-bhatia1@ti.com> Regards Aradhya > 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 0affcefdeb1c..137a9f5e3cad 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); > } >
diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c index 0affcefdeb1c..137a9f5e3cad 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); }
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_connector_get_modes() 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.kiszka@siemens.com> Closes: https://lore.kernel.org/all/24282420-b4dd-45b3-bb1c-fc37fe4a8205@siemens.com/ Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> --- drivers/gpu/drm/bridge/tc358767.c | 7 +++++++ 1 file changed, 7 insertions(+)