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From: "Billie Alsup (balsup)" <balsup@cisco.com>
To: Armin Wolf <W_Armin@gmx.de>
Cc: "linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
	Len Brown <lenb@kernel.org>
Subject: Re: 32-bit versus 64-bit ACPI tables
Date: Mon, 6 May 2024 17:15:27 +0000	[thread overview]
Message-ID: <SJ0PR11MB6624A48E0FF0FA4D0D89D773D91C2@SJ0PR11MB6624.namprd11.prod.outlook.com> (raw)
In-Reply-To: <2cd5a3d5-ed29-48c7-bb70-e660aff5c0d2@gmx.de>


>From: Armin Wolf <W_Armin@gmx.de>
>the ACPI specification says that the integer length for _both_ DSDT and SSDT tables
>is controlled by the revision field of the DSDT, so your 32-bit DSDT prevents your
>SSDT from using 64-bit integers.

I see you are correct.  The ACPI Spec 6.5 explicitly states as much.

>The only solution for this would be to not use 64-bit values inside your SSDT, is
>there a reason why you absolutely need 64-bit integers in your DSDT?

It would be a convenience to encode a 64-bit match value in _ADR (for example, while
using acpi_find_child_device).  However, I can certainly use other attributes and walk
the child nodes myself.  In other cases, where I really want a 64-bit mask, I can resort
to an array, or distinct named fields.  It just seemed unnecessarily awkward.  I think
the real solution, as painful as it may seem, is to get our firmware team to switch to 
ComplianceRevision 2 for the DSDT.

Thanks for your insights!


      parent reply	other threads:[~2024-05-06 17:16 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-01 17:05 32-bit versus 64-bit ACPI tables Billie Alsup (balsup)
2024-05-05 16:25 ` Armin Wolf
2024-05-06 11:04   ` Rafael J. Wysocki
2024-05-06 17:15   ` Billie Alsup (balsup) [this message]

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