Debug LCD

  1. Follow the steps in Test Case Configuration to configure the test environment.
    Note: Make sure you have configured libdrm and modetest before compiling and burning an image.
  2. After you have completed the kernel start-up, use the following command to verify the display functions and connection status. 
    modetest -M starfive
    The following legends and tables display an example output and descriptions.
    • Debug output 1:
      Figure 1. Debug Display 1
      Table 1. Debug Display 1
      Legend Label Description
      ① possible crtcs Available Cathode Ray Tube Controller (CRTC) devices
      ② status Whether the display connector is connected or not
      ③ name The name (type) of the display connector
      ④ encoders The connected encoders
      ⑤ modes The supported display modes
      ⑥ value The Extended Display Identification Data (EDID) of the screen
    • Debug output 2:
      Figure 2. Debug Display 2
      Table 2. Debug Display 2
      Legend Label Description
      ① id The CRTC 0x00000001 mentioned in row ① of table Debug Display 1, which means the CRTC is available for use.
      ② id The CRTC 0x00000002 mentioned in row ① of table Debug Display 1, which means the CRTC is available for use.
      Note: If the displayed CRTC is 0x00000003, both of the CRTCs are available for use.
    • Debug output 3:
      Figure 3. Debug Display 3
      Table 3. Debug Display 3
      Legend Description
      ① The CRTC and its connected plane
  • Check MIPI connect status:
    Figure 4. MIPI Connect Status

    The common connector ID of MIPI is 118. If both rgb2hdmi and MIPI panel are registered, the connector ID of MIPI will be assigned as 120.