> ## 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.

# Configure alternate device drivers

## Enable camera overlays

<Note>
  This section applies only to QCS6490, IQ-9075, and IQ-8275.
</Note>

When you flash and boot qcom-multimedia-proprietary-image, the upstream camera
stack is enabled by default. You can change this setting by updating the EFI
variable.

Update the EFI variable at runtime after the device boots. On the first boot,
set the EFI variable using the sysfs node and then reboot to enable CAMX on
subsequent boots.

Run the following steps to enable camera overlay:

* Store the driver name `camx` in a temporary file. Command uses `-n` flag to
  ensure the content doesn't have any trailing new characters.
  ```bash theme={null}
  echo -n "camx" > /tmp/overlay
  ```

* The EFI variable used to control the overlays loaded during UEFI boot is
  `882f8c2b-9646-435f-8de5-f208ff80c1bd-VendorDtbOverlays`. Use `efivar` to
  write the data into the runtime EFI variable.
  ```bash theme={null}
  efivar -n 882f8c2b-9646-435f-8de5-f208ff80c1bd-VendorDtbOverlays -w -f /tmp/overlay
  ```

* Print the EFI variable to confirm if the updates have been made:
  ```bash theme={null}
  efivar -n 882f8c2b-9646-435f-8de5-f208ff80c1bd-VendorDtbOverlays -p
  ```

* Reboot the device to enable the new driver:
  ```bash theme={null}
  sync
  reboot
  ```

* After rebooting, you can check the UEFI serial logs to verify that the camx
  overlay has been applied:
  ```text Sample output for IQ-9075-EVK theme={null}
  Variable VendorDtbOverlays read successfully. Data: camx
  ProcessQcomRuntimeOverlayRequest: Parsed camx

  FindConfigToBoot:Booting with = qcom,qcs8275-iot-camx
  FindConfigToBoot: i = 0 fdt fdt-monaco-evk.dtb str len = 18
  FindConfigToBoot: i = 1 fdt fdt-monaco-evk-camx.dtbo str len = 24
  ParseFitDt::
  Config fdt-monaco-evk.dtb & Type 0
  Config fdt-monaco-evk-camx.dtbo & Type 1
  FitLoadDtbFromFdt: Config fdt-monaco-evk.dtb & Type 0
  FitLoadDtbFromFdt: Config fdt-monaco-evk-camx.dtbo & Type 1
  ```

## Enable upstream video driver

<Note>
  This section applies only to IQ-615 EVK.
</Note>

IQ‑615 EVK only supports the upstream video driver `venus`. The video overlay
functionality is not supported.

When you flash and boot `qcom-multimedia-proprietary-image`, the upstream video
driver is not enabled by default. This can be changed by updating the kernel
module configuration.

* Enable the upstream video driver:
  ```bash theme={null}
  update-alternatives --install /etc/modprobe.d/blacklist-video.conf blacklist-video /etc/modprobe.d/blacklist-video.conf.vidc 200
  ```

* Reboot the device and run `lsmod` to confirm if the changes have been applied:

  ```bash theme={null}
  lsmod | grep venus
  ```

  ```text Expected output theme={null}
  venus_enc           28672   0
  venus_dec           28672   0
  ```