The sta_himax83102 panel sometimes shows abnormally flickering
horizontal lines. The front gate output will precharge the X point of
the next pole circuit before TP(TouchPanel Enable) term starts, and wait
until the end of the TP term to resume the CLK. For this reason, the X
point must be maintained during the TP term. In abnormal case, we
measured a slight leakage at point X. This because during the TP term,
the GPW does not fully pull the VGL low, causing the TFT to not be
closed tightly.
To fix this, we completely pull GPW to VGL before entering the TP term.
This will ensure that the TFT is closed tightly and prevent the abnormal
display.
Fixes: 1bc2ef065f13 ("drm/panel: Support for Starry-himax83102-j02 TDDI MIPI-DSI panel")
Signed-off-by: Ruihai Zhou <zhouruihai@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
---
Changes since v1:
- Rebased on top of drm-misc-next
- Add Fixes tag from Jessica's comment
v1: https://patchwork.kernel.org/project/dri-devel/patch/20230912105932.16618-1-zhouruihai@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
---
drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c b/drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c
index 5ac926281d2c..c9087f474cbc 100644
--- a/drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c
+++ b/drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c
@@ -1342,9 +1342,7 @@ static const struct panel_init_cmd starry_himax83102_j02_init_cmd[] = {
_INIT_DCS_CMD(0xB1, 0x01, 0xBF, 0x11),
_INIT_DCS_CMD(0xCB, 0x86),
_INIT_DCS_CMD(0xD2, 0x3C, 0xFA),
- _INIT_DCS_CMD(0xE9, 0xC5),
- _INIT_DCS_CMD(0xD3, 0x00, 0x00, 0x00, 0x00, 0x80, 0x0C, 0x01),
- _INIT_DCS_CMD(0xE9, 0x3F),
+ _INIT_DCS_CMD(0xD3, 0x00, 0x00, 0x44, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0x0C, 0x01),
_INIT_DCS_CMD(0xE7, 0x02, 0x00, 0x28, 0x01, 0x7E, 0x0F, 0x7E, 0x10, 0xA0, 0x00, 0x00, 0x20, 0x40, 0x50, 0x40),
_INIT_DCS_CMD(0xBD, 0x02),
_INIT_DCS_CMD(0xD8, 0xFF, 0xFF, 0xBF, 0xFE, 0xAA, 0xA0, 0xFF, 0xFF, 0xBF, 0xFE, 0xAA, 0xA0),
