dw-hdmi can operate in two different modes, depending on the platform data
as set by the driver:
A. hdmi->plat_data->output_port = 0:
the HDMI output (port@1) in device tree is not used
B. hdmi->plat_data->output_port = 1:
the HDMI output (port@1) is parsed to find the next bridge
Only case B is supported when the DRM_BRIDGE_ATTACH_NO_CONNECTOR flag is
passed to the attach callback. Emit a warning when this is violated. Also
return -EINVAL which would be returned by drm_bridge_attach() right after
anyway.
Reviewed-by: Liu Ying <[email protected]>
Tested-by: Martyn Welch <[email protected]>
Tested-by: Alexander Stein <[email protected]> #
TQMa8MPxL/MBa8MPxL
Signed-off-by: Luca Ceresoli <[email protected]>
---
Note: Returning when the warning triggers does not change the functional
behaviour of this function. It is not strictly necessary in this patch but
it will have to be done anyway in the following patch.
---
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index 0296e110ce65..ab1a6a8783cd 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -2910,6 +2910,10 @@ static int dw_hdmi_bridge_attach(struct drm_bridge
*bridge,
{
struct dw_hdmi *hdmi = bridge->driver_private;
+ /* DRM_BRIDGE_ATTACH_NO_CONNECTOR requires a remote-endpoint to the
next bridge */
+ if (WARN_ON((flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) &&
!hdmi->plat_data->output_port))
+ return -EINVAL;
+
if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
return drm_bridge_attach(encoder, hdmi->bridge.next_bridge,
bridge, flags);
--
2.53.0
