Components further up in the chain might ask us for supported formats.
Without this MEDIA_BUS_FMT_FIXED is assumed which then breaks display
output with mxsfb since it can't determine a proper bus format.
We handle the bus formats that correspond to the DSI formats the bridge
can potentially output (see chapter 13.6 of the i.MX 8MQ reference
manual) - which matches what xsfb can input.
Fixes: b776b0f00f24 ("drm: mxsfb: Use bus_format from the nearest bridge if present")
Signed-off-by: Guido Günther <agx@xxxxxxxxxxx>
---
drivers/gpu/drm/bridge/nwl-dsi.c | 35 ++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)
diff --git a/drivers/gpu/drm/bridge/nwl-dsi.c b/drivers/gpu/drm/bridge/nwl-dsi.c
index a251cc1f088f..27c80d36846b 100644
--- a/drivers/gpu/drm/bridge/nwl-dsi.c
+++ b/drivers/gpu/drm/bridge/nwl-dsi.c
@@ -1234,6 +1234,40 @@ static void nwl_dsi_bridge_detach(struct drm_bridge *bridge)
drm_of_panel_bridge_remove(dsi->dev->of_node, 1, 0);
}
+static u32 *nwl_bridge_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
+ struct drm_bridge_state *bridge_state,
+ struct drm_crtc_state *crtc_state,
+ struct drm_connector_state *conn_state,
+ u32 output_fmt,
+ unsigned int *num_input_fmts)
+{
+ u32 *input_fmts, input_fmt;
+
+ *num_input_fmts = 0;
+
+ switch (output_fmt) {
+ /* If MEDIA_BUS_FMT_FIXED is tested, return default bus format */
+ case MEDIA_BUS_FMT_FIXED:
+ input_fmt = MEDIA_BUS_FMT_RGB888_1X24;
+ break;
+ case MEDIA_BUS_FMT_RGB888_1X24:
+ case MEDIA_BUS_FMT_RGB666_1X18:
+ case MEDIA_BUS_FMT_RGB565_1X16:
+ input_fmt = output_fmt;
+ break;
+ default:
+ return NULL;
+ }
+
+ input_fmts = kcalloc(1, sizeof(*input_fmts), GFP_KERNEL);
+ if (!input_fmts)
+ return NULL;
+ input_fmts[0] = input_fmt;
+ *num_input_fmts = 1;
+
+ return input_fmts;
+}
+
static const struct drm_bridge_funcs nwl_dsi_bridge_funcs = {
.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
@@ -1241,6 +1275,7 @@ static const struct drm_bridge_funcs nwl_dsi_bridge_funcs = {
.atomic_check = nwl_dsi_bridge_atomic_check,
.atomic_enable = nwl_dsi_bridge_atomic_enable,
.atomic_disable = nwl_dsi_bridge_atomic_disable,
+ .atomic_get_input_bus_fmts = nwl_bridge_atomic_get_input_bus_fmts,
.mode_set = nwl_dsi_bridge_mode_set,
.mode_valid = nwl_dsi_bridge_mode_valid,
.attach = nwl_dsi_bridge_attach,
--
2.33.0
