> ## Documentation Index
> Fetch the complete documentation index at: https://dragonwingdocs.qualcomm.com/llms.txt
> Use this file to discover all available pages before exploring further.

# IQ-9075

## 调试 DisplayPort

<Note>
  * 您必须启用 SSH 才能访问主机设备。有关说明，请参阅[使用 SSH 登录](https://dragonwingdocs.qualcomm.com/Key-Documents/Flash-Guide/how-to-sign-in-with-ssh)。
  * 要挂载 `debugfs` 文件系统以访问显示子系统的 `debugfs` 详细信息，请运行以下命令：

  > ```text theme={null}
  > mount -o remount,rw /
  > ```

  > ```text theme={null}
  > mount -t debugfs none /sys/kernel/debug
  > ```
</Note>

**查看所选的 DisplayPort**

要检查所选的 DisplayPort，请运行以下命令：

> ```text theme={null}
> cat /sys/kernel/debug/dri/0/DP-1/dp_debug
> ```

**示例输出**

```text theme={null}
name = msm_dp
drm_dp_link
        rate = 270000
        num_lanes = 4
        capabilities = 1
dp_panel_info:
        active = 3840x2160
        back_porch = 80x23
        front_porch = 48x3
        sync_width = 32x5
        active_low = 0x0
        h_skew = 0
        refresh rate = 30
        pixel clock khz = 262750
        bpp = 30
dp_link:
        test_requested = 512
        num_lanes = 4
        bw_code = 10
        lclk = 270000000
        v_level = 1
        p_level = 0
```

**查看 DisplayPort 线缆状态**

要检查 DisplayPort 连接情况，请运行以下命令：

> ```text theme={null}
> cat /sys/class/drm/card0-DP-1/status
> ```

**示例输出**

```text theme={null}
Connected
```

**检查扩展显示识别数据（EDID）模式**

要检查所连接 DisplayPort 的 EDID 模式，请运行以下命令：

> ```text theme={null}
> cat /sys/class/drm/card0-DP-1/modes
> ```

**示例输出**

```text theme={null}
3840x2160
2048x1080
```