Re: [PATCH 1/3] MFD: introduce lpc_sch for Intel SCH LPC bridge

[Denis Turischev]

Jean Delvare wrote:
> On Tue, 16 Feb 2010 11:57:46 -0800, David Brownell wrote:
> > On Thursday 11 February 2010, Denis Turischev wrote:
> > > Intel Poulsbo (SCH) chipset LPC bridge controller contains several
> > > functions. Creating and MFD driver for the LPC bridge controller allows
> > Spelling nit: "Creating an" (not and).  Keyboard, brain, or edit fault.  ;)
> >
> >
> > > simultaneous use of SMBus and GPIO interfaces on the SCH.
> > This looks like the right way to package such southbridge level
> > componentry.  Maye not just these two interfaces, either.
> >
> > But ... how does this play with ACPI?  The last several Intel
> > systems I looked at seemed to expect ACPI to manage GPIOs and the
> > IRQs they may issue.  (He wrote, staring at an ICH8-system where
> > ACPI uses GPIOs to manage several buttons and LEDs.)
> >
> > It would seem error-prone to ignore that coupling on systems
> > with ACPI.  Linux has enough trouble sorting out issues caused
> > by buggy AML (ACPI bytecode) without introducing conflicts in
> > who manages which hardware resource (ACPI vs. operating system).
>
> Might be a good idea to use acpi_check_resource_conflict() or similar
> before instantiating the platform devices.

May be it worth to add such resource check directly to mfd_add_device function?

> > Of course, if ACPI weren't being used to hide such board-specific
> > details from operating systems, such issues would not exist.  But
> > such hiding is one of the basic goals of ACPI ... annoying.
>
> Don't start me on this :(

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