What are the steps to bring up a DSI panel?

Autonomous Machines Jetson & Embedded Systems Jetson TX1
1

Hello,

Ive been trying to bring up a DSI panel for a while. Can someone explain in simple terms the steps to configure and bring up a DSI panel on the TX1 Jetson?

Thank you in advance!

2

m-walker,

Please note that below steps are only for tx1. TX2 would have other setting to setup.

Start from what you flash to tegra.

  1. There is a default DSI enabled on TX1. To enable this board, you need to flash p2371-2180.conf under Linux_for_Tegra.

  2. You could check this line under that config → BCFFILE=“bootloader/t210ref/cfg/board_config_p2597.xml”;

  3. There would be a field named “display” and id = 1937.

  4. Check “kernel/display/drivers/video/tegra/dc/panel/board-panel.c” → internal_panel_select_by_disp_board_id

and you will see case BOARD_E1937, which matches the id. It would set is_dsi_a_1200_1920_8_0 to 1.

  1. That setting in step 4 would set up a ops
if (np_panel && pdata && dc_out)                                                                                                                                                           
                         tegra_panel_register_ops(dc_out,                                                                                                                                                   
                                 &dsi_a_1200_1920_8_0_ops);

  1. You could refer to “panel-a-1200-1920-8-0.c”. We call it “the panel driver” for panel-a-1200_1920.

  2. dc.c → tegra_dc_probe is the one that use those ops.

3

Add some logs in above files would be helpful for debug.

4

Thank you for your quick reply!

I followed your steps and I made the following modifications to board-panel.c

static void tegra_pwm_bl_ops_reg_based_on_disp_board_id(struct device *dev)
{
	struct board_info display_board;

	<b>bool is_dsi_a_1200_1920_8_0 = true;</b>
	bool is_dsi_a_1200_800_8_0 = false;
	bool is_edp_i_1080p_11_6 = false;
	bool is_edp_a_1080p_14_0 = false;
	bool is_edp_s_2160p_15_6 = false;

static struct device_node
	*internal_panel_select_by_disp_board_id(
		struct tegra_dc_platform_data *pdata)
{
	struct device_node *np_panel = NULL;
	struct tegra_dc_out *dc_out = NULL;
	struct board_info display_board;

	<b>bool is_dsi_a_1200_1920_8_0 = true;</b>
	bool is_dsi_a_1200_800_8_0 = false;
	bool is_edp_i_1080p_11_6 = false;
	bool is_edp_a_1080p_14_0 = false;
	bool is_edp_s_2160p_15_6 = false;

case BOARD_E1937:
			if (np_panel && pdata && dc_out)
				tegra_panel_register_ops(dc_out,
					&dsi_a_1200_1920_8_0_ops);

Here is the log error messages

[    0.511745] DC OR NODE connected to /host1x/sor1
[    0.511838] display board info: id 0xffff, fab 0x0
[    0.512092] panel_select fail by _node_status
[    0.512148] display board info: id 0xffff, fab 0x0
[    0.512374] panel_select fail by _node_status
[    0.512401] generic_infoframe_type: 0x87
[    0.512577] tegradc tegradc.1: DT parsed successfully
[    0.512633] tegradc tegradc.1: Display dc.ffffff8000980000 registered with id=0
[    0.513396] display board info: id 0xffff, fab 0x0
[    0.513645] panel_select fail by _node_status

What would be causing this issue?

5 
np_dsi = of_find_node_by_path(DSI_NODE);
  	if (np_dsi) {
  		for_each_available_child_of_node(np_dsi, np_panel) {
  			if (np_panel)
  				break;
  		}
  	}

This error comes because your device tree seems wrong. Please refer to our ours.

6

Hello WayneWWW,
Thank you for your reply!

Can you give me an example of how to modify the tegra210-jetson-cv-base-p2597-2180-a00.dts and tegra210-jetson-tx1-p2597-2180-a01-devkit.dts what other files should I modify?

7

tegra210-jetson-cv-base-p2597-2180-a00.dts already includes the part of DSI dt.