[Intel-gfx] [PATCH v3] ACPI / bus: Introduce a list of ids for "always present" devices

[Lukas Wunner]

On Sat, Apr 08, 2017 at 05:05:11PM +0200, Hans de Goede wrote:
> Several cherrytrail devices (all of which ship with windows 10) hide the
> lpss pwm controller in ACPI, typically the _STA method looks like this:
> 
>     Method (_STA, 0, NotSerialized)  // _STA: Status
>     {
>         If (OSID == One)
>         {
>             Return (Zero)
>         }
> 
>         Return (0x0F)
>     }
> 
> Where OSID is some dark magic seen in all cherrytrail ACPI tables making
> the machine behave differently depending on which OS it *thinks* it is
> booting, this gets set in a number of ways which we cannot control, on
> some newer machines it simple hardcoded to "One" aka win10.

Would it be a viable alternative to respond differently to _OSI queries
for these devices by amending acpi_osi_dmi_table[] in drivers/acpi/osi.c?


> +		pr_debug("Device [%s] is in always present list setting status [%08x]\n",
> +			 adev->pnp.bus_id, ACPI_STA_DEFAULT);

In a lot of places in drivers/acpi/, dev_warn(&adev->dev, ...) is used.

Otherwise LGTM.

Thanks,

Lukas