For MNC207QS1-1 panel, Splash screen occur when switch from VT1 to VT2.
The BL_EN signal does not conform to the VESA protocol.
BL_EN signal needs to be pulled high after video signal.
So add prepare_to_enable to 200ms.

Signed-off-by: Zhengqiao Xia <xiazhengqiao@huaqin.corp-partner.google.com>
---
 drivers/gpu/drm/panel/panel-edp.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/panel/panel-edp.c b/drivers/gpu/drm/panel/panel-edp.c
index d58f90bc48fb..745f3e48f02a 100644
--- a/drivers/gpu/drm/panel/panel-edp.c
+++ b/drivers/gpu/drm/panel/panel-edp.c
@@ -1865,6 +1865,13 @@ static const struct panel_delay delay_200_500_e50 = {
 	.enable = 50,
 };
 
+static const struct panel_delay delay_200_500_e50_p2e200 = {
+	.hpd_absent = 200,
+	.unprepare = 500,
+	.enable = 50,
+	.prepare_to_enable = 200,
+};
+
 static const struct panel_delay delay_200_500_e80 = {
 	.hpd_absent = 200,
 	.unprepare = 500,
@@ -2034,7 +2041,7 @@ static const struct edp_panel_entry edp_panels[] = {
 	EDP_PANEL_ENTRY('C', 'M', 'N', 0x14d6, &delay_200_500_e80_d50, "N140BGA-EA4"),
 	EDP_PANEL_ENTRY('C', 'M', 'N', 0x14e5, &delay_200_500_e80_d50, "N140HGA-EA1"),
 
-	EDP_PANEL_ENTRY('C', 'S', 'O', 0x1200, &delay_200_500_e50, "MNC207QS1-1"),
+	EDP_PANEL_ENTRY('C', 'S', 'O', 0x1200, &delay_200_500_e50_p2e200, "MNC207QS1-1"),
 
 	EDP_PANEL_ENTRY('H', 'K', 'C', 0x2d51, &delay_200_500_e200, "Unknown"),
 	EDP_PANEL_ENTRY('H', 'K', 'C', 0x2d5b, &delay_200_500_e200, "Unknown"),
-- 
2.17.1

Hi,

On Fri, Mar 1, 2024 at 12:40 AM Zhengqiao Xia
<xiazhengqiao@huaqin.corp-partner.google.com> wrote:
>
> For MNC207QS1-1 panel, Splash screen occur when switch from VT1 to VT2.
> The BL_EN signal does not conform to the VESA protocol.
> BL_EN signal needs to be pulled high after video signal.
> So add prepare_to_enable to 200ms.
>
> Signed-off-by: Zhengqiao Xia <xiazhengqiao@huaqin.corp-partner.google.com>
> ---
>  drivers/gpu/drm/panel/panel-edp.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)

Should have:

Fixes: 0547692ac146 ("drm/panel-edp: Add several generic edp panels")

Also note that the subject tag "drm/panel-edp" is much more common
than others for this file and probably better to use that than
"drm/panel: panel-edp".

Other than that this looks fine to me. Applying to drm-misc-next since
the patch this is fixing isn't in mainline yet and this doesn't seem
massively urgent.

e635b7eb7062 drm/panel-edp: Add prepare_to_enable to 200ms for MNC207QS1-1

-Doug