drm/fb-helper: Eliminate the .best_encoder() usage

Instead of using the .best_encoder() hook to figure out whether a given
connector+crtc combo will work, let's instead do what userspace does and
just iterate over all the encoders for the connector, and then check
each crtc against each encoder's possible_crtcs bitmask.

v2: Avoid oopsing on NULL encoders (Daniel)
    s/connector_crtc_ok/connector_has_possible_crtc/

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180628131315.14156-2-ville.syrjala@linux.intel.com

1 files changed, 24 insertions, 17 deletions

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index cab14f253384..b37f06317d51 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -2323,6 +2323,27 @@ retry:
         return true;
 }
 
+static bool connector_has_possible_crtc(struct drm_connector *connector,
+                                        struct drm_crtc *crtc)
+{
+        int i;
+
+        for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
+                struct drm_encoder *encoder;
+
+                if (connector->encoder_ids[i] == 0)
+                        break;
+
+                encoder = drm_encoder_find(connector->dev, NULL,
+                                           connector->encoder_ids[i]);
+
+                if (encoder->possible_crtcs & drm_crtc_mask(crtc))
+                        return true;
+        }
+
+        return false;
+}
+
 static int drm_pick_crtcs(struct drm_fb_helper *fb_helper,
                           struct drm_fb_helper_crtc **best_crtcs,
                           struct drm_display_mode **modes,
@@ -2331,7 +2352,6 @@ static int drm_pick_crtcs(struct drm_fb_helper *fb_helper,
         int c, o;
         struct drm_connector *connector;
         const struct drm_connector_helper_funcs *connector_funcs;
-        struct drm_encoder *encoder;
         int my_score, best_score, score;
         struct drm_fb_helper_crtc **crtcs, *crtc;
         struct drm_fb_helper_connector *fb_helper_conn;
@@ -2363,27 +2383,14 @@ static int drm_pick_crtcs(struct drm_fb_helper *fb_helper,
         connector_funcs = connector->helper_private;
 
         /*
-         * If the DRM device implements atomic hooks and ->best_encoder() is
-         * NULL we fallback to the default drm_atomic_helper_best_encoder()
-         * helper.
-         */
-        if (drm_drv_uses_atomic_modeset(fb_helper->dev) &&
-            !connector_funcs->best_encoder)
-                encoder = drm_atomic_helper_best_encoder(connector);
-        else
-                encoder = connector_funcs->best_encoder(connector);
-
-        if (!encoder)
-                goto out;
-
-        /*
          * select a crtc for this connector and then attempt to configure
          * remaining connectors
          */
         for (c = 0; c < fb_helper->crtc_count; c++) {
                 crtc = &fb_helper->crtc_info[c];
 
-                if ((encoder->possible_crtcs & (1 << c)) == 0)
+                if (!connector_has_possible_crtc(connector,
+                                                 crtc->mode_set.crtc))
                         continue;
 
                 for (o = 0; o < n; o++)
@@ -2410,7 +2417,7 @@ static int drm_pick_crtcs(struct drm_fb_helper *fb_helper,
                                sizeof(struct drm_fb_helper_crtc *));
                 }
         }
-out:
+
         kfree(crtcs);
         return best_score;
 }