Re: [BUG] OV02C10 on Dell 16 Premium DA16250 (ARL): INT3472 handshake-derived "dvdd" regulator registered but never linked to sensor, sensor probe fails with -EREMOTEIO

[Marco Nenciarini <mnencia@kcore.it>]

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Samuele,

Thanks. The dvdd re-key worked (post-patch ov02c10 only logs "not
found" for dovdd/avdd, not dvdd, so it did attach to DSC0's dvdd), but
as you found it can't bring the sensor up: the rails it still needs
(avdd, dovdd, its reset GPIO and clock) would have come from DSC1, and
DSC1 is _STA=0, so nothing live provides them.

So before any kernel change is worth considering, the question is
whether DSC1 is off by firmware design. _STA=0 is what you get from a
device that is BIOS-disabled, OS-gated, or simply not fitted on this
SKU, and the asymmetry fits: DSC0 (the IR camera) is live, only DSC1
(the RGB sensor) is dead. If DSC1 is meant to be off here, there is
nothing for int3472 to fix and no quirk worth writing, so I'd rather
confirm that than build around it.

The way to tell is to read DSC1's _STA from the firmware tables.
acpidump's multi-table dump won't feed iasl -d directly, so read the
raw tables from sysfs:

    cp /sys/firmware/acpi/tables/DSDT dsdt.dat
    cp /sys/firmware/acpi/tables/SSDT* .
    iasl -d dsdt.dat SSDT*

then grep the *.dsl for DSC1 (the DSC blocks often live in an SSDT, not
the DSDT) and read its _STA. If it returns a flat zero, or gates on
_OSI("Windows ..."), or reads a manufacturing/setup variable, the
sensor is disabled by firmware and that is the end of the kernel angle.
If instead it depends on something a live instance could satisfy, then
there's a kernel path worth pursuing and we look again.

If you still have the factory Windows install, whether the RGB camera
works there is a useful cross-check (works in Windows means gated, not
absent), but the _STA read is the real signal.

Thanks,
Marco
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