Re: [PATCH v8 1/2] ACPI:RAS2: Add ACPI RAS2 driver

[Yazen Ghannam <yazen.ghannam@amd.com>]

On Thu, Jun 12, 2025 at 04:29:50PM +0000, Shiju Jose wrote:

[...]

> >
> >Just curious, would the new "faux" bus work for this use case?
> 
> I tried with "faux" interface, following are the observations.
> 1. RAS2 scrub control interface do present and work under /sys/bus/faux/devices/...
>     as expected. However it does not appear under /sys/bus/edac/devices/... as required.
>    It seems that the reason for this is that, with the faux device, the RAS2 faux probe function 
>    and thus edac_dev_register() is called during the early boot stage, compared to the probe
>     of the present auxiliary device based solution. 
>     I think EDAC is not fully initialized at that boot stage?
>     This issue is solved with late_initcall(acpi_ras2_init) instead of calling acpi_ras2_init()
>     from  acpi_init() (drivers/acpi/bus.c). 
>    
> 2.  The faux_device_create() function takes a struct faux_device_ops *, which requires the
>       faux_device_ops for RAS2 to be defined within this driver (drivers/acpi/ras2.c). Therefore,
>       registration with EDAC for RAS features may necessitate moving to a *ras2_faux_probe()
>        function here. This would also require moving the struct edac_scrub_ops ras2_scrub_ops and
>         the corresponding callback functions from drivers/ras/acpi_ras2.c to this location.
>        Alternatively, we could add and export a ras2_faux_init() function in drivers/ras/acpi_ras2.c
>        and call it from *ras2_faux_probe().
> 
> Thus not sure  "faux" is a suitable interface for RAS2?
> 

Right, maybe not. Or could be something to look at later.

I only became aware of the "faux" interface recently, so I just thought
to ask. :)

Thanks,
Yazen