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Debug the high-definition multimedia interface (HDMI) display

You can do the following to debug your HDMI display:
  • Upgrade the Lontium firmware
  • View display serial interface (DSI) clock information
Upgrade Lontium firmware LT9611uxc is the DSI-to-HDMI bridge chip firmware. The recommended firmware version is LT9611UXC_DSI_PortA_HDCP_Disable_V5.0.21.bin. If you experience a no-display screen on the HDMI, upgrade the firmware. To upgrade the Lontium firmware, do the following:
  1. Download the recommended LT9611uxc firmware version LT9611UXC_DSI_PortA_HDCP_Disable_V5.0.21.bin from the Lontium website and go to the Qualcomm section.
    • Enable SSH to access your host device. For more information, see Sign in using SSH.
    • When prompted for a password, enter oelinux123.
  2. To upgrade the firmware, run the following Linux shell command: 
    mount -o rw,remount /usr
    Close SSH and copy the Lontium firmware using the following scp command:
    scp <LT firmware bin> root@<IP of the device>:/lib/firmware/lt9611uxc_fw.bin
    Before running the following command, enable SSH again.
    sync

    echo 0 > /sys/bus/i2c/devices/0-002b/lt9611uxc_firmware
    Wait for at least 3 minutes for the firmware upgrade to complete.
  3. To retrieve the lt9611 logs, run the following command: 
    dmesg | grep lt9611
The Firmware updates successfully log confirms that the firmware upgrade is successful. To ensure that the new firmware is in effect, perform a hard reboot (unplug and plug in the power cable) of the device. View the DSI clock information
  • You must enable SSH to access your host device. For instructions, see Sign in using SSH.
  • To mount the debugfs file system to access the debugfs details of the display subsystem, run the following commands:
mount -o remount,rw /

mount -t debugfs none /sys/kernel/debug
To check the DSI clock information, run the following command: 
cat /sys/kernel/debug/clk/disp_cc_mdss_pclk0_clk/clk_rate