6.12-stable review patch. If anyone has any objections, please let me know.
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From: Tomi Valkeinen tomi.valkeinen@ideasonboard.com
[ Upstream commit 2d343723c7e1f9f6d64f721f07cfdfc2993758d1 ]
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.kiszka@siemens.com Closes: https://lore.kernel.org/all/24282420-b4dd-45b3-bb1c-fc37fe4a8205@siemens.com... Fixes: de5e6c027ae6 ("drm/bridge: tc358767: add drm_panel_bridge support") Reviewed-by: Aradhya Bhatia a-bhatia1@ti.com Tested-by: Jan Kiszka jan.kiszka@siemens.com Signed-off-by: Tomi Valkeinen tomi.valkeinen@ideasonboard.com Link: https://patchwork.freedesktop.org/patch/msgid/20231108-tc358767-v2-2-25c5f70... Signed-off-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 f3afdab55c113..47189587643a1 100644 --- a/drivers/gpu/drm/bridge/tc358767.c +++ b/drivers/gpu/drm/bridge/tc358767.c @@ -1714,6 +1714,13 @@ static const struct drm_edid *tc_edid_read(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_edid_read_ddc(connector, &tc->aux.ddc); }