1 files changed, 22 insertions, 3 deletions

diff --git a/drivers/gpu/drm/vc4/vc4_dpi.c b/drivers/gpu/drm/vc4/vc4_dpi.c
index 72c9dbd81d7f..f185812970da 100644
--- a/drivers/gpu/drm/vc4/vc4_dpi.c
+++ b/drivers/gpu/drm/vc4/vc4_dpi.c
@@ -96,7 +96,6 @@ struct vc4_dpi {
         struct platform_device *pdev;
 
         struct drm_encoder *encoder;
-        struct drm_connector *connector;
 
         void __iomem *regs;
 
@@ -164,14 +163,31 @@ static void vc4_dpi_encoder_disable(struct drm_encoder *encoder)
 
 static void vc4_dpi_encoder_enable(struct drm_encoder *encoder)
 {
+        struct drm_device *dev = encoder->dev;
         struct drm_display_mode *mode = &encoder->crtc->mode;
         struct vc4_dpi_encoder *vc4_encoder = to_vc4_dpi_encoder(encoder);
         struct vc4_dpi *dpi = vc4_encoder->dpi;
+        struct drm_connector_list_iter conn_iter;
+        struct drm_connector *connector = NULL, *connector_scan;
         u32 dpi_c = DPI_ENABLE | DPI_OUTPUT_ENABLE_MODE;
         int ret;
 
-        if (dpi->connector->display_info.num_bus_formats) {
-                u32 bus_format = dpi->connector->display_info.bus_formats[0];
+        /* Look up the connector attached to DPI so we can get the
+         * bus_format.  Ideally the bridge would tell us the
+         * bus_format we want, but it doesn't yet, so assume that it's
+         * uniform throughout the bridge chain.
+         */
+        drm_connector_list_iter_begin(dev, &conn_iter);
+        drm_for_each_connector_iter(connector_scan, &conn_iter) {
+                if (connector_scan->encoder == encoder) {
+                        connector = connector_scan;
+                        break;
+                }
+        }
+        drm_connector_list_iter_end(&conn_iter);
+
+        if (connector && connector->display_info.num_bus_formats) {
+                u32 bus_format = connector->display_info.bus_formats[0];
 
                 switch (bus_format) {
                 case MEDIA_BUS_FMT_RGB888_1X24:
@@ -199,6 +215,9 @@ static void vc4_dpi_encoder_enable(struct drm_encoder *encoder)
                         DRM_ERROR("Unknown media bus format %d\n", bus_format);
                         break;
                 }
+        } else {
+                /* Default to 24bit if no connector found. */
+                dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB, DPI_FORMAT);
         }
 
         if (mode->flags & DRM_MODE_FLAG_NHSYNC)