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Message-ID: <CA+5PVA4EBdoxgSrYKYRnaO2qSXDP_rxeQEogD+6jkKPi8sQB-g@mail.gmail.com>
Date: Fri, 30 Mar 2012 09:14:53 -0400
From: Josh Boyer <jwboyer@...il.com>
To: Len Brown <lenb@...nel.org>
Cc: linux-acpi@...r.kernel.org, linux-pm@...ts.linux-foundation.org,
linux-kernel@...r.kernel.org, Julian Anastasov <ja@....bg>,
Len Brown <len.brown@...el.com>
Subject: Re: [PATCH 04/76] ACPICA: Fix regression in FADT revision checks
On Fri, Mar 30, 2012 at 6:13 AM, Len Brown <lenb@...nel.org> wrote:
> From: Julian Anastasov <ja@....bg>
>
> commit 64b3db22c04586997ab4be46dd5a5b99f8a2d390 (2.6.39),
> "Remove use of unreliable FADT revision field" causes regression
> for old P4 systems because now cst_control and other fields are
> not reset to 0.
>
> The effect is that acpi_processor_power_init will notice
> cst_control != 0 and a write to CST_CNT register is performed
> that should not happen. As result, the system oopses after the
> "No _CST, giving up" message, sometimes in acpi_ns_internalize_name,
> sometimes in acpi_ns_get_type, usually at random places. May be
> during migration to CPU 1 in acpi_processor_get_throttling.
>
> Every one of these settings help to avoid this problem:
> - acpi=off
> - processor.nocst=1
> - maxcpus=1
>
> The fix is to update acpi_gbl_FADT.header.length after
> the original value is used to check for old revisions.
>
> https://bugzilla.kernel.org/show_bug.cgi?id=42700
> https://bugzilla.redhat.com/show_bug.cgi?id=727865
>
> Signed-off-by: Julian Anastasov <ja@....bg>
> Acked-by: Bob Moore <robert.moore@...el.com>
> Signed-off-by: Len Brown <len.brown@...el.com>
This one should go into the stable trees. The bug it fixes causes a
number of machines to not boot with anything newer than 2.6.38.
josh
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