Re: [tpmdd-devel] [PATCH v2 0/3] tpm_tis: Clean up force module parameter

[Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>]

On Mon, Dec 07, 2015 at 10:52:51AM +0100, Wilck, Martin wrote:
> > > > You can completely ignore this question. I saw Martins reply with a fix for
> > > > "tpm_tis: Use devm_ioremap_resource" that you should squash into that
> > > > change. So it's proved that TPM ACPI device objects do not always have a
> > > > memory resource. Good.
> > > 
> > > Repeat, the memory resource DOES exist on my system. Not sure what proof
> > > you saw there.
> > 
> > Ok, lets go this through.
> > 
> > I deduced this from two facts:
> > 
> > * It used to have memory resource as conditional and as a fallback use
> >   fixed value.
> > * Your workaround reverted the situation to this.
> > 
> > Did I understand something incorrectly?
> 
> The problem in my case didn't occur because ACPI was lacking a resource.
> It has one "extra" resource that Jason's original code didn't
> recognize. 
> 
> Jason's code was wrongly assuming that a resource that isn't of type
> "IRQ" has to be of type "MEMORY". If I print out the resource types
> encountered in tpm_check_resource(), I get
> ACPI_RESOURCE_TYPE_FIXED_MEMORY32  (0x0a) first, followed by
> ACPI_RESOURCE_TYPE_END_TAG (0x07). The latter was mistakenly used by
> Jason't code as a memory resource. This is how ACPI ResourceTemplates
> work (a list with an end marker). The correct solution is to always
> check the return value of acpi_dev_resource_memory(), as it's currently
> implemented in Jason't current "for-jarkko" branch.

Aah. Right.

> Martin

/Jarkko