IMX8ULP DSI output waveform is different from imx8mm

[tangchao90]

i need output 1080p30 by dsi from imx8ulp, my dts configure is 

&dsi {
status = "okay";

panel@0 {
compatible = "hetos,mipi7";
reg = <0>;
port {
panel_in: endpoint {
remote-endpoint = <&mipi_dsi_out>;
};
};
};

ports {
port@1 {
reg = <1>;

mipi_dsi_out: endpoint {
remote-endpoint = <&panel_in>;
};
};
};
};

in fact  i do something in drivers/gpu/drm/panel/panel-simple.c

static const struct drm_display_mode hetos_mipi7_mode = {

        .clock = 74250,

        .hdisplay = 1920,

        .hsync_start = 2008,

        .hsync_end = 2052,

        .htotal = 2200,

        .vdisplay = 1080,

        .vsync_start = 1084,

        .vsync_end = 1089,

        .vtotal = 1125,

};

static const struct panel_desc_dsi hetos_mipi7 = {

        .desc = {

                .modes = &hetos_mipi7_mode,

                .num_modes = 1,

                .bpc = 8,

                .size = {

                        .width = 170,

                        .height = 110,

                },

                .bus_format = MEDIA_BUS_FMT_RGB888_1X24,

                .connector_type = DRM_MODE_CONNECTOR_DPI,

        },

        .flags = MIPI_DSI_CLOCK_NON_CONTINUOUS | MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_SYNC_PULSE | MIPI_DSI_MODE_LPM,

        .format = MIPI_DSI_FMT_RGB888,

        .lanes = 4,

};

but i find it can't work well in my bridge，at the same time it can work well in imx8mm,

i compare imx8ulp with imx8mm in the same configure, i find the waveform is different

imx8mm waveform

imx8ulp waveform

i want to now why?

[Zhiming_Liu]

Hello,

They have different DSI IP and driver, please try to use DRM_MODE_CONNECTOR_DSI for .connector_type

Best Regards,
Zhiming

[tangchao90]

hello 

    My first connector_type is DRM_MODE_CONNECTOR_DSI . but it wasn't effective, i changed it to  DRM_MODE_CONNECTOR_DPI, but the result waveform is the same

[Zhiming_Liu]

Hello,

The DSI in i.MX8ULP can't support 1080p30.

The supported resolution are here:

Best Regards,
Zhiming

[tangchao90]

of course i set the max_height and max_width to 1920 in dcnano-kms.c file