kmscube.c: init_drm(): handle usecase where display is disabled

In some usecases HDMI is connected but is disabled by default.
In such scenario, connector->encoder_id and encoder->crtc_id
may be 0. This patch iterates over all possible encoders and
CRTCs to find and store the encoder and CRTC accordingly.

Signed-off-by: Eric Ruei <e-ruei1@ti.com>

diff --git a/kmscube.c b/kmscube.c
index 6bfa86a0f1d7b6cd30a7f10ada3f414814b398af..9dbefa346b6e8f0ce44e95ca9314c73d8ddc0887 100644 (file)
--- a/kmscube.c
+++ b/kmscube.c
@@ -91,7 +91,7 @@ static int init_drm(void)
        drmModeEncoder *encoder = NULL;
        drmModeCrtc *crtc = NULL;
 
-       int i, j;
+       int i, j, k;
        uint32_t maxRes, curRes;
 
        for (i = 0; i < ARRAY_SIZE(modules); i++) {
@@ -123,18 +123,49 @@ static int init_drm(void)
                if (connector->connection == DRM_MODE_CONNECTED) {
 
                        /* find the matched encoders */
-                       for (j=0; j<resources->count_encoders; j++) {
-                               encoder = drmModeGetEncoder(drm.fd, resources->encoders[j]);
+                       for (j=0; j<connector->count_encoders; j++) {
+                               encoder = drmModeGetEncoder(drm.fd, connector->encoders[j]);
+
+                               /* Take the fisrt one, if none is assigned */
+                               if (!connector->encoder_id)
+                               {
+                                       connector->encoder_id = encoder->encoder_id;
+                               }
+
                                if (encoder->encoder_id == connector->encoder_id)
+                               {
+                                       /* find the first valid CRTC if not assigned */
+                                       if (!encoder->crtc_id)
+                                       {
+                                               for (k = 0; k < resources->count_crtcs; ++k) {
+                                                       /* check whether this CRTC works with the encoder */
+                                                       if (!(encoder->possible_crtcs & (1 << k)))
+                                                               continue;
+
+                                                       encoder->crtc_id = resources->crtcs[k];
+                                                       break;
+                                               }
+
+                                               if (!encoder->crtc_id)
+                                               {
+                                                       printf("Encoder(%d): no CRTC find!\n", encoder->encoder_id);
+                                                       drmModeFreeEncoder(encoder);
+                                                       encoder = NULL;
+                                                       continue;
+                                               }
+                                       }
+
                                        break;
+                               }
 
                                drmModeFreeEncoder(encoder);
                                encoder = NULL;
                        }
 
                        if (!encoder) {
-                               printf("no encoder!\n");
-                               return -1;
+                               printf("Connector (%d): no encoder!\n", connector->connector_id);
+                               drmModeFreeConnector(connector);
+                               continue;
                        }
 
                        /* choose the current or first supported mode */