When multiple bridges are present, EDID detection capability
(DRM_BRIDGE_OP_EDID) takes precedence over modes detection
(DRM_BRIDGE_OP_MODES). To ensure the above two capabilities are
determined by the last bridge in the chain, we handle three cases:
Case 1: The later bridge declares only DRM_BRIDGE_OP_MODES
- If the previous bridge declares DRM_BRIDGE_OP_EDID, set
&drm_bridge_connector.bridge_edid to NULL and set
&drm_bridge_connector.bridge_modes to the later bridge.
- Ensure modes detection capability of the later bridge will not
be ignored.
Case 2: The later bridge declares only DRM_BRIDGE_OP_EDID
- If the previous bridge declares DRM_BRIDGE_OP_MODES, set
&drm_bridge_connector.bridge_modes to NULL and set
&drm_bridge_connector.bridge_edid to the later bridge.
- Although EDID detection capability has higher priority, this
operation is for balance and makes sense.
Case 3: the later bridge declares both of them
- Assign later bridge as &drm_bridge_connector.bridge_edid and
and &drm_bridge_connector.bridge_modes to this bridge.
- Just leave transfer of these two capabilities as before.
Signed-off-by: Damon Ding <damon.ding@rock-chips.com>
Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
Changes in v7:
- As Luca suggested, simplify the code and related comment.
Changes in v8:
- Adapt the modifications to the newest bridge_connector driver.
---
drivers/gpu/drm/display/drm_bridge_connector.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
index a2d30cf9e06d..92b9e8ec520d 100644
--- a/drivers/gpu/drm/display/drm_bridge_connector.c
+++ b/drivers/gpu/drm/display/drm_bridge_connector.c
@@ -690,9 +690,19 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
if (!bridge->ycbcr_420_allowed)
connector->ycbcr_420_allowed = false;
- if (bridge->ops & DRM_BRIDGE_OP_EDID) {
+ /*
+ * Ensure the last bridge declares OP_EDID or OP_MODES or both.
+ */
+ if (bridge->ops & DRM_BRIDGE_OP_EDID || bridge->ops & DRM_BRIDGE_OP_MODES) {
drm_bridge_put(bridge_connector->bridge_edid);
- bridge_connector->bridge_edid = drm_bridge_get(bridge);
+ bridge_connector->bridge_edid = NULL;
+ drm_bridge_put(bridge_connector->bridge_modes);
+ bridge_connector->bridge_modes = NULL;
+
+ if (bridge->ops & DRM_BRIDGE_OP_EDID)
+ bridge_connector->bridge_edid = drm_bridge_get(bridge);
+ if (bridge->ops & DRM_BRIDGE_OP_MODES)
+ bridge_connector->bridge_modes = drm_bridge_get(bridge);
}
if (bridge->ops & DRM_BRIDGE_OP_HPD) {
drm_bridge_put(bridge_connector->bridge_hpd);
@@ -702,10 +712,6 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
drm_bridge_put(bridge_connector->bridge_detect);
bridge_connector->bridge_detect = drm_bridge_get(bridge);
}
- if (bridge->ops & DRM_BRIDGE_OP_MODES) {
- drm_bridge_put(bridge_connector->bridge_modes);
- bridge_connector->bridge_modes = drm_bridge_get(bridge);
- }
if (bridge->ops & DRM_BRIDGE_OP_HDMI) {
if (bridge_connector->bridge_hdmi)
return ERR_PTR(-EBUSY);
--
2.34.1