linux-kernel - [PATCH v3 1/2] drm/panel: jd9365da: Modify Kingdisplay and Melfas panel timing

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Message-Id: <20240927094340.18544-2-lvzhaoxiong@huaqin.corp-partner.google.com>
Date: Fri, 27 Sep 2024 17:43:39 +0800
From: Zhaoxiong Lv <lvzhaoxiong@...qin.corp-partner.google.com>
To: neil.armstrong@...aro.org,
	quic_jesszhan@...cinc.com,
	sam@...nborg.org,
	maarten.lankhorst@...ux.intel.com,
	mripard@...nel.org,
	tzimmermann@...e.de,
	airlied@...il.com,
	simona@...ll.ch,
	dianders@...omium.org,
	hsinyi@...gle.com,
	awarnecke002@...mail.com,
	dmitry.baryshkov@...aro.org
Cc: dri-devel@...ts.freedesktop.org,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Zhaoxiong Lv <lvzhaoxiong@...qin.corp-partner.google.com>
Subject: [PATCH v3 1/2] drm/panel: jd9365da: Modify Kingdisplay and  Melfas panel timing

In MTK chips, if the DRM runtime resume has not yet completed and the
system enters sleep mode at the same time, there is a possibility of
a black screen after waking the machine. Reduce the disable delay
resolves this issue,

The "backlight_off_to_display_off_delay_ms" was added between
"backlight off" and "display off"  to prevent "display off" from being
executed when the backlight is not fully powered off, which may cause
a white screen. However, we removed this
"backlight_off_to_display_off_delay_ms" and found that this situation
did not occur. Therefore, in order to solve the problem mentioned
above, we reduced it from 100ms to 3ms (tCMD_OFF >= 1ms).

This is the timing specification for the two panels:
1. Kingdisplay panel timing spec:
https://github.com/KD54183/-JD9365DA_Power-On-Off-Sequence_V0120240923
2. LMFBX101117480 timing spec: https://github.com/chiohsin-lo/TDY-JD_LIB

Fixes: 2b976ad760dc ("drm/panel: jd9365da: Support for kd101ne3-40ti MIPI-DSI panel")
Fixes: c4ce398cf18a ("drm/panel: jd9365da: Support for Melfas lmfbx101117480 MIPI-DSI panel")

Signed-off-by: Zhaoxiong Lv <lvzhaoxiong@...qin.corp-partner.google.com>
---
Changes between V3 and V2:
-  1. Modify the commit message 
v2: https://lore.kernel.org/all/20240923134227.11383-2-lvzhaoxiong@huaqin.corp-partner.google.com/

Changes between V2 and V1:
-  1. Modify the commit message 
-  2. Modify the value of backlight_off_to_display_off_delay_ms.
v1: https://lore.kernel.org/all/20240915080830.11318-2-lvzhaoxiong@huaqin.corp-partner.google.com/
---
 drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c b/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c
index 44897e5218a6..486aa20e5518 100644
--- a/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c
+++ b/drivers/gpu/drm/panel/panel-jadard-jd9365da-h3.c
@@ -858,7 +858,7 @@ static const struct jadard_panel_desc kingdisplay_kd101ne3_40ti_desc = {
 	.reset_before_power_off_vcioo = true,
 	.vcioo_to_lp11_delay_ms = 5,
 	.lp11_to_reset_delay_ms = 10,
-	.backlight_off_to_display_off_delay_ms = 100,
+	.backlight_off_to_display_off_delay_ms = 3,
 	.display_off_to_enter_sleep_delay_ms = 50,
 	.enter_sleep_to_reset_down_delay_ms = 100,
 };
@@ -1109,7 +1109,7 @@ static const struct jadard_panel_desc melfas_lmfbx101117480_desc = {
 	.reset_before_power_off_vcioo = true,
 	.vcioo_to_lp11_delay_ms = 5,
 	.lp11_to_reset_delay_ms = 10,
-	.backlight_off_to_display_off_delay_ms = 100,
+	.backlight_off_to_display_off_delay_ms = 3,
 	.display_off_to_enter_sleep_delay_ms = 50,
 	.enter_sleep_to_reset_down_delay_ms = 100,
 };
-- 
2.17.1