Calculate video start delay based on the display timing instead of hardcoding it to a default value. This fixes "trembling" display output on Asus Transformer TF700T which uses Panasonic VVX10F004B00 display panel.
Tested-by: Andreas Westman Dorcsak hedmoo@yahoo.com # Asus TF700T Tested-by: Maxim Schwalm maxim.schwalm@gmail.com #TF700T Signed-off-by: Dmitry Osipenko digetx@gmail.com --- drivers/gpu/drm/bridge/tc358768.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c index 10ebd0621ad3..5b3f8723bd3d 100644 --- a/drivers/gpu/drm/bridge/tc358768.c +++ b/drivers/gpu/drm/bridge/tc358768.c @@ -634,7 +634,8 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge) u32 val, val2, lptxcnt, hact, data_type; const struct drm_display_mode *mode; u32 dsibclk_nsk, dsiclk_nsk, ui_nsk, phy_delay_nsk; - u32 dsiclk, dsibclk; + u32 dsiclk, dsibclk, video_start; + const u32 internal_delay = 40; int ret, i;
tc358768_hw_enable(priv); @@ -663,23 +664,27 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge) case MIPI_DSI_FMT_RGB888: val |= (0x3 << 4); hact = mode->hdisplay * 3; + video_start = (mode->htotal - mode->hsync_start) * 3; data_type = MIPI_DSI_PACKED_PIXEL_STREAM_24; break; case MIPI_DSI_FMT_RGB666: val |= (0x4 << 4); hact = mode->hdisplay * 3; + video_start = (mode->htotal - mode->hsync_start) * 3; data_type = MIPI_DSI_PACKED_PIXEL_STREAM_18; break;
case MIPI_DSI_FMT_RGB666_PACKED: val |= (0x4 << 4) | BIT(3); hact = mode->hdisplay * 18 / 8; + video_start = (mode->htotal - mode->hsync_start) * 18 / 8; data_type = MIPI_DSI_PIXEL_STREAM_3BYTE_18; break;
case MIPI_DSI_FMT_RGB565: val |= (0x5 << 4); hact = mode->hdisplay * 2; + video_start = (mode->htotal - mode->hsync_start) * 2; data_type = MIPI_DSI_PACKED_PIXEL_STREAM_16; break; default: @@ -690,7 +695,8 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge) }
/* VSDly[9:0] */ - tc358768_write(priv, TC358768_VSDLY, 1); + video_start = max(video_start, internal_delay + 1) - internal_delay; + tc358768_write(priv, TC358768_VSDLY, video_start);
tc358768_write(priv, TC358768_DATAFMT, val); tc358768_write(priv, TC358768_DSITX_DT, data_type);