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add instructions for enabling CAMX module - #30

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sjakki88 merged 1 commit into
dragonwing-docs:mainfrom
abinjose-qualcomm:enable-dtb-overlay
Feb 24, 2026
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sjakki88 merged 1 commit into
dragonwing-docs:mainfrom
abinjose-qualcomm:enable-dtb-overlay

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CAMX module is not enabled by default for
qcom-multimedia-prop-image. While long term solutions are being discussed, add an immediate solution to allow users to experience the downstream CAMX solution.


# The -n option is mandatory because EFI variables
# expect exact data without trailing newline characters.
echo -n "camx" > /var/data

@ricardosalveti ricardosalveti Feb 21, 2026 •

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Use /tmp/overlay instead or similar, /var is not recommended for temporary data like this one.


# Use efivar to write the data into the runtime EFI variable
# Format: <GUID>-<Variable Name>
cd /sys/firmware/efi/efivar/

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No need to cd into this folder, it is also incorrect, should be /sys/firmware/efi/efivars/

When you flash and boot ``qcom-multimedia-proprietary-image`` for the first time,
the upstream camera stack is enabled by default. Build time blacklisting cannot
help here since blacklisting upstream CAMSS modules does not lead to CAMX being
loaded.

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I don't think we need to say that blacklisting cannot help here, best to just say what is required and later explain why.


On first boot, the user needs to set the EFI variable via the sysfs node and
reboot to get CAMX enabled in subsequent boots. EFI variable setting can only be
done after booting up once.

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Only be done after booting up once is a bit confusing, I would instead just say that EFI variable setting needs to be done at runtime, after booting the device.

# Use efivar to write the data into the runtime EFI variable
# Format: <GUID>-<Variable Name>
cd /sys/firmware/efi/efivar/
efivar -n 882f8c2b-9646-435f-8de5-f208ff80c1bd-VendorDtbOverlays -w -f /var/data

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We should also say above (before the commands), that the EFI variable used to control the overlays loaded during UEFI boot is 882f8c2b-9646-435f-8de5-f208ff80c1bd-VendorDtbOverlays.

CAMX module is not enabled by default for
qcom-multimedia-prop-image. While long term solutions
are being discussed, add an immediate solution to allow
users to experience the downstream CAMX solution.

Signed-off-by: Abin Joseph <abinjose@qti.qualcomm.com>
@ricardosalveti

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Please also don't forget to go back to the comments explaining what you changed, helps moving the review forward.

@sjakki88 sjakki88 left a comment

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Looks good to me.

@sjakki88
sjakki88 merged commit bb0dde9 into dragonwing-docs:main Feb 24, 2026
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3 participants