Re: [Qemu-devel] [PATCH] Add option to disable FDC from ISA bus and ACPI on i386

[Paolo Bonzini]

Il 08/01/2014 22:09, Gabriel L. Somlo ha scritto:
> On Wed, Jan 08, 2014 at 10:38:21PM +0200, Michael S. Tsirkin wrote:
>>> > > +        /* _STA will be patched to 0x0F if the FDC is present */
>>> > > +        ACPI_EXTRACT_NAME_WORD_CONST DSDT_FDC_STA
>>> > > +        Name(_STA, 0xFF00)
>> > 
>> > I'm not sure why this is WORD. Spec says bits 0-4 have meaning bits up
>> > to 31 are cleared. So should not this be either dword (to make all
>> > 32 bits explicit) or byte (to make it small)?
> You're right of course, _STA returns 32 bits, 5 of which are defined,
> and the rest are reserved and "must be cleared".
> 
> As such, I think it should be DWORD (and I'm not confident enough to
> be sure no breakage would occur if we go "BYTE" instead :) )

Byte should work.  Internally, the AML interpreter treats all integers
as either 32-bit or 64-bit depending on the version.

Paolo