drm/omap: Get rid of DRM_OMAP_NUM_CRTCS config option

Allocate one CRTC for each connected output and get rid of
DRM_OMAP_NUM_CRTCS config option. We still can not create more CRTCs
than we have DSS display managers. We also reserve one overlay per
CRTC for primary plane so we can not have more CRTCs than we have
overlays either.

Signed-off-by: Jyri Sarha <[e-mail]>
Reviewed-by: Laurent Pinchart <[e-mail]>
Signed-off-by: Tomi Valkeinen <[e-mail]>

drivers/gpu/drm/omapdrm/Kconfig

···
 
 if DRM_OMAP
 
-config DRM_OMAP_NUM_CRTCS
-	int "Number of CRTCs"
-	range 1 10
-	default 1  if ARCH_OMAP2 || ARCH_OMAP3
-	default 2  if ARCH_OMAP4
-	help
-	  Select the number of video overlays which can be used as framebuffers.
-	  The remaining overlays are reserved for video.
-
 source "drivers/gpu/drm/omapdrm/dss/Kconfig"
 source "drivers/gpu/drm/omapdrm/displays/Kconfig"
 

drivers/gpu/drm/omapdrm/omap_drv.c

···
 #define DRIVER_MINOR		0
 #define DRIVER_PATCHLEVEL	0
 
-static int num_crtc = CONFIG_DRM_OMAP_NUM_CRTCS;
-
-MODULE_PARM_DESC(num_crtc, "Number of overlays to use as CRTCs");
-module_param(num_crtc, int, 0600);
-
 /*
  * mode config funcs
  */
···
 	struct omap_dss_device *dssdev = NULL;
 	int num_ovls = priv->dispc_ops->get_num_ovls();
 	int num_mgrs = priv->dispc_ops->get_num_mgrs();
-	int num_crtcs;
+	int num_crtcs = 0;
 	int i, id = 0;
 	int ret;
 	u32 possible_crtcs;
···
 		return ret;
 
 	/*
-	 * We usually don't want to create a CRTC for each manager, at least
-	 * not until we have a way to expose private planes to userspace.
-	 * Otherwise there would not be enough video pipes left for drm planes.
-	 * We use the num_crtc argument to limit the number of crtcs we create.
+	 * Let's create one CRTC for each connected DSS device if we
+	 * have display managers and overlays (for primary planes) for
+	 * them.
 	 */
-	num_crtcs = min3(num_crtc, num_mgrs, num_ovls);
+	for_each_dss_dev(dssdev)
+		if (omapdss_device_is_connected(dssdev))
+			num_crtcs++;
+
+	num_crtcs = min3(num_crtcs, num_mgrs, num_ovls);
 	possible_crtcs = (1 << num_crtcs) - 1;
 
 	dssdev = NULL;
···
 		drm_mode_connector_attach_encoder(connector, encoder);
 
 		/*
-		 * if we have reached the limit of the crtcs we are allowed to
-		 * create, let's not try to look for a crtc for this
-		 * panel/encoder and onwards, we will, of course, populate the
-		 * the possible_crtcs field for all the encoders with the final
-		 * set of crtcs we create
+		 * if we have reached the limit of the crtcs we can
+		 * create, let's not try to create a crtc for this
+		 * panel/encoder and onwards.
 		 */
 		if (id == num_crtcs)
 			continue;
···
 	}
 
 	/*
-	 * we have allocated crtcs according to the need of the panels/encoders,
-	 * adding more crtcs here if needed
-	 */
-	for (; id < num_crtcs; id++) {
-
-		/* find a free manager for this crtc */
-		for (i = 0; i < num_mgrs; i++) {
-			if (!channel_used(dev, i))
-				break;
-		}
-
-		if (i == num_mgrs) {
-			/* this shouldn't really happen */
-			dev_err(dev->dev, "no managers left for crtc\n");
-			return -ENOMEM;
-		}
-
-		ret = omap_modeset_create_crtc(dev, id, i,
-			possible_crtcs);
-		if (ret < 0) {
-			dev_err(dev->dev,
-				"could not create CRTC (channel %u)\n", i);
-			return ret;
-		}
-	}
-
-	/*
 	 * Create normal planes for the remaining overlays:
 	 */
 	for (; id < num_ovls; id++) {
···
 		priv->planes[priv->num_planes++] = plane;
 	}
 
+	/*
+	 * populate the the possible_crtcs field for all the encoders
+	 * we created.
+	 */
 	for (i = 0; i < priv->num_encoders; i++) {
 		struct drm_encoder *encoder = priv->encoders[i];
 		struct omap_dss_device *dssdev =