Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) client-ip=23.128.96.37;
From:   Hsin-Yi Wang <hsinyi@chromium.org>
To:     Douglas Anderson <dianders@chromium.org>
Cc:     Neil Armstrong <neil.armstrong@linaro.org>,
        Jessica Zhang <quic_jesszhan@quicinc.com>,
        Sam Ravnborg <sam@ravnborg.org>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org
Subject: [PATCH v5 4/4] drm/panel-edp: Avoid adding multiple preferred modes
Date:   Mon,  6 Nov 2023 15:51:35 -0800
Message-ID: <20231107000023.2928195-5-hsinyi@chromium.org>
In-Reply-To: <20231107000023.2928195-1-hsinyi@chromium.org>
References: <20231107000023.2928195-1-hsinyi@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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 <hsinyi@chromium.org>
---
v4->v5: remove inapplicable comments.
---
 drivers/gpu/drm/panel/panel-edp.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-edp.c b/drivers/gpu/drm/panel/panel-edp.c
index c0c24d94c3a0..006939cc3fee 100644
--- a/drivers/gpu/drm/panel/panel-edp.c
+++ b/drivers/gpu/drm/panel/panel-edp.c
@@ -589,6 +589,7 @@ 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;
@@ -599,7 +600,11 @@ 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
@@ -616,12 +621,7 @@ static int panel_edp_get_modes(struct drm_panel *panel,
 		pm_runtime_put_autosuspend(panel->dev);
 	}
 
-	/*
-	 * Add hard-coded panel modes. Don't call this if there are no timings
-	 * 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