Re: [PATCH -next 1/2] i2c: designware: Switch from using MMIO access to SMN access

Jan Dąbroś
2022-09-26T14:33:56Z

Hi Borislav,

czw., 22 wrz 2022 o 16:29 Hans de Goede <hdegoede@redhat.com> napisał(a):
>
> Hi,
>
> On 9/22/22 16:04, Borislav Petkov wrote:
> > On Thu, Sep 22, 2022 at 03:48:07PM +0200, Hans de Goede wrote:
> >> Right, thank you for Cc-ing me. At least on X86 there are several platforms
> >> (and 100-s of device models) which use a PMIC connected to the i2c-designware
> >> controller and this PMIC gets poked directly from ACPI _S0 and _S3
> >> (power on/off) methods. So the I2C bus driver needs to *bind* to the controller
> >> as soon as we find its description in ACPI, otherwise we get a whole bunch
> >> of failed ACPI OpRegion access errors as well as various actual really issues.
> >
> > Thanks for explaining - I couldn't find the reason why it has to be a
> > subsys_initcall.
> >
> >> So please keep this as a subsys initcall.
> >
> > Which means, init_amd_nbs() would have to be sorted to run before
> > dw_i2c_init_driver()...
>
> Yes if possible. One solution might be to make it a arch_initcall_sync()
> which AFAIK runs after regular arch_initcall()-s but before subsys_initcall()-s.

What do you think about this?

Best Regards,
Jan