> ## 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.

# QCS6490

## 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](https://www.lontiumsemi.com/download) website and go to the Qualcomm section.

   <Note>
     * Enable SSH to access your host device. For more information, see [Sign in using SSH](https://dragonwingdocs.qualcomm.com/Key-Documents/Flash-Guide/how-to-sign-in-with-ssh).
     * When prompted for a password, enter `oelinux123`.
   </Note>

2. To upgrade the firmware, run the following Linux shell command:

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

   <Note>Close SSH and copy the Lontium firmware using the following `scp` command:</Note>

   > ```text theme={null}
   > scp <LT firmware bin> root@<IP of the device>:/lib/firmware/lt9611uxc_fw.bin
   > ```

   <Note>Before running the following command, enable SSH again.</Note>

   > ```text theme={null}
   > sync
   > ```

   > ```text theme={null}
   > echo 0 > /sys/bus/i2c/devices/0-002b/lt9611uxc_firmware
   > ```

   <Note>Wait for at least 3 minutes for the firmware upgrade to complete.</Note>

3. To retrieve the lt9611 logs, run the following command:

   > ```text theme={null}
   > 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**

<Note>
  * You must enable SSH to access your host device. For instructions, see [Sign in using SSH](https://dragonwingdocs.qualcomm.com/Key-Documents/Flash-Guide/how-to-sign-in-with-ssh).
  * To mount the `debugfs` file system to access the `debugfs` details of the display subsystem, run the following commands:

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

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

To check the DSI clock information, run the following command:

> ```text theme={null}
> cat /sys/kernel/debug/clk/disp_cc_mdss_pclk0_clk/clk_rate
> ```