From: Dio Zhang <dioyc_zhang@compal.corp-partner.google.com>

Screen garbage or flickering can be observed during mode changes(such
as VT switches) on systems using the AUO B116XAK01.6 and B140XTK02.4
panels.

This occurs because the backlight is enabled before the video signal
stabilizes. Waveform measurements show that the panel signal takes 
around 140ms to stabilize after a mode change, meaning the previous 50ms T8
timing was insufficient.

To resolve this issue, adjust the eDP panel delay entry from
delay_200_500_e50 to delay_200_500_e200 (increasing T8 from 50ms to 200ms).
This matches the updated panel specifications from AUO, which now formally
define T8 as 200ms to mask any display abnormalities during mode changes.

Signed-off-by: Dio Zhang <dioyc_zhang@compal.corp-partner.google.com>
---
 drivers/gpu/drm/panel/panel-edp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-edp.c b/drivers/gpu/drm/panel/panel-edp.c
index 8d3859cd3ddc..3a168bfffd4e 100644
--- a/drivers/gpu/drm/panel/panel-edp.c
+++ b/drivers/gpu/drm/panel/panel-edp.c
@@ -2055,7 +2055,7 @@ static const struct edp_panel_entry edp_panels[] = {
 	EDP_PANEL_ENTRY('A', 'U', 'O', 0x145c, &delay_200_500_e50, "B116XAB01.4"),
 	EDP_PANEL_ENTRY('A', 'U', 'O', 0x1999, &delay_200_500_e50, "Unknown"),
 	EDP_PANEL_ENTRY('A', 'U', 'O', 0x1e9b, &delay_200_500_e50, "B133UAN02.1"),
-	EDP_PANEL_ENTRY('A', 'U', 'O', 0x1ea5, &delay_200_500_e50, "B116XAK01.6"),
+	EDP_PANEL_ENTRY('A', 'U', 'O', 0x1ea5, &delay_200_500_e200, "B116XAK01.6"),
 	EDP_PANEL_ENTRY('A', 'U', 'O', 0x203d, &delay_200_500_e50, "B140HTN02.0"),
 	EDP_PANEL_ENTRY('A', 'U', 'O', 0x208d, &delay_200_500_e50, "B140HTN02.1"),
 	EDP_PANEL_ENTRY('A', 'U', 'O', 0x235c, &delay_200_500_e50, "B116XTN02.3"),
@@ -2074,7 +2074,7 @@ static const struct edp_panel_entry edp_panels[] = {
 	EDP_PANEL_ENTRY('A', 'U', 'O', 0x615c, &delay_200_500_e50, "B116XAN06.1"),
 	EDP_PANEL_ENTRY('A', 'U', 'O', 0x635c, &delay_200_500_e50, "B116XAN06.3"),
 	EDP_PANEL_ENTRY('A', 'U', 'O', 0x639c, &delay_200_500_e50, "B140HAK02.7"),
-	EDP_PANEL_ENTRY('A', 'U', 'O', 0x67a8, &delay_200_500_e50, "B140XTK02.4"),
+	EDP_PANEL_ENTRY('A', 'U', 'O', 0x67a8, &delay_200_500_e200, "B140XTK02.4"),
 	EDP_PANEL_ENTRY('A', 'U', 'O', 0x723c, &delay_200_500_e50, "B140XTN07.2"),
 	EDP_PANEL_ENTRY('A', 'U', 'O', 0x73aa, &delay_200_500_e50, "B116XTN02.3"),
 	EDP_PANEL_ENTRY('A', 'U', 'O', 0x8594, &delay_200_500_e50, "B133UAN01.0"),
-- 
2.34.1

Hi,

On Sun, Jul 19, 2026 at 7:54 PM dioyc_zhang
<dioyc_zhang@compal.corp-partner.google.com> wrote:
>
> From: Dio Zhang <dioyc_zhang@compal.corp-partner.google.com>
>
> Screen garbage or flickering can be observed during mode changes(such
> as VT switches) on systems using the AUO B116XAK01.6 and B140XTK02.4
> panels.
>
> This occurs because the backlight is enabled before the video signal
> stabilizes. Waveform measurements show that the panel signal takes
> around 140ms to stabilize after a mode change, meaning the previous 50ms T8
> timing was insufficient.
>
> To resolve this issue, adjust the eDP panel delay entry from
> delay_200_500_e50 to delay_200_500_e200 (increasing T8 from 50ms to 200ms).
> This matches the updated panel specifications from AUO, which now formally
> define T8 as 200ms to mask any display abnormalities during mode changes.
>
> Signed-off-by: Dio Zhang <dioyc_zhang@compal.corp-partner.google.com>
> ---
>  drivers/gpu/drm/panel/panel-edp.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

A few notes:

* Your email client is still slightly misconfigured in regards to real
name. As you can see, when I quoted your message above it still says
"On Sun, Jul 19, 2026 at 7:54 PM dioyc_zhang <..." instead of "On Sun,
Jul 19, 2026 at 7:54 PM Dio Zhang <...". In any case, at least the
patch authorship and Signed-off-by look fine. Just something to try to
improve for the next patch. ;-)

* The patch doesn't apply cleanly to drm-misc-next. Presumbly you sent
it based on an older tree. Ideally, send patches against drm-misc-next
for panel-edp. I've fixed it up this time, but it's an extra step for
me.

* Subject line only referenced one of the two panels. I've fixed this
up for you.


Reviewed-by: Douglas Anderson <dianders@chromium.org>

Pushed to drm-misc-next:

[1/1] drm/panel: panel-edp: Adjust T8 timing for AUO B116XAK01.6 and B140XTK02.4
      commit: 0d40cab39158704e372240ed9821a00bfe117125

-Doug