linux-kernel - [PATCH v2 4/4] drm/panel-edp: Choose correct preferred mode

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Message-ID: <20231102221309.1971910-5-hsinyi@chromium.org>
Date:   Thu,  2 Nov 2023 14:47:50 -0700
From:   Hsin-Yi Wang <hsinyi@...omium.org>
To:     Douglas Anderson <dianders@...omium.org>
Cc:     Neil Armstrong <neil.armstrong@...aro.org>,
        Jessica Zhang <quic_jesszhan@...cinc.com>,
        Sam Ravnborg <sam@...nborg.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 4/4] drm/panel-edp: Choose correct preferred mode

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 a hard-coded mode is present, unset the preferred bit of the modes read
from edid.

Signed-off-by: Hsin-Yi Wang <hsinyi@...omium.org>
---
v1->v2: split patches from drm_modes.
---
 drivers/gpu/drm/panel/panel-edp.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-edp.c b/drivers/gpu/drm/panel/panel-edp.c
index 0fb439b5efb1..021322ff9f65 100644
--- a/drivers/gpu/drm/panel/panel-edp.c
+++ b/drivers/gpu/drm/panel/panel-edp.c
@@ -622,10 +622,13 @@ 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 (p->desc->num_timings || p->desc->num_modes) {
+		/* hard-coded modes present, unset preferred modes from edid. */
+		drm_mode_unset_preferred_modes(connector);
 		num += panel_edp_get_non_edid_modes(p, connector);
-	else if (!num)
+	} else if (!num) {
 		dev_warn(p->base.dev, "No display modes\n");
+	}
 
 	/*
 	 * TODO: Remove once all drm drivers call
-- 
2.42.0.869.gea05f2083d-goog