[PATCH v4 3/3] drm/panel-edp: Avoid adding multiple preferred modes

[Hsin-Yi Wang]

If a non generic edp-panel is under aux-bus, the mode read from edid would
still be selected as preferred and results in multiple preferred modes,
which is ambiguous.

If both hard-coded mode and edid exists, only add mode from hard-coded.

Signed-off-by: Hsin-Yi Wang <hsi...@chromium.org>
---
v3->v4: don't skip read edid. only skip add modes.
---
 drivers/gpu/drm/panel/panel-edp.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-edp.c 
b/drivers/gpu/drm/panel/panel-edp.c
index 0fb439b5efb1..c8bb4baf1d45 100644
--- a/drivers/gpu/drm/panel/panel-edp.c
+++ b/drivers/gpu/drm/panel/panel-edp.c
@@ -590,6 +590,7 @@ static int panel_edp_get_modes(struct drm_panel *panel,
 {
        struct panel_edp *p = to_panel_edp(panel);
        int num = 0;
+       bool has_hard_coded_modes = p->desc->num_timings || p->desc->num_modes;
        bool has_override_edid_mode = p->detected_panel &&
                                      p->detected_panel != ERR_PTR(-EINVAL) &&
                                      p->detected_panel->override_edid_mode;
@@ -600,7 +601,11 @@ static int panel_edp_get_modes(struct drm_panel *panel,
 
                if (!p->edid)
                        p->edid = drm_get_edid(connector, p->ddc);
-               if (p->edid) {
+               /*
+                * If both edid and hard-coded modes exists, skip edid modes to
+                * avoid multiple preferred modes.
+                */
+               if (p->edid && !has_hard_coded_modes) {
                        if (has_override_edid_mode) {
                                /*
                                 * override_edid_mode is specified. Use
@@ -622,7 +627,7 @@ static int panel_edp_get_modes(struct drm_panel *panel,
         * and no modes (the generic edp-panel case) because it will clobber
         * the display_info that was already set by drm_add_edid_modes().
         */
-       if (p->desc->num_timings || p->desc->num_modes)
+       if (has_hard_coded_modes)
                num += panel_edp_get_non_edid_modes(p, connector);
        else if (!num)
                dev_warn(p->base.dev, "No display modes\n");
-- 
2.42.0.869.gea05f2083d-goog