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* [PATCH] ACPICA: Fix regression in FADT revision checks
@ 2012-02-23 20:40 Julian Anastasov
  2012-02-23 21:55 ` Moore, Robert
  2012-02-27 19:50 ` Len Brown
  0 siblings, 2 replies; 3+ messages in thread
From: Julian Anastasov @ 2012-02-23 20:40 UTC (permalink / raw)
  To: Len Brown; +Cc: linux-acpi

	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.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
---
 drivers/acpi/acpica/tbfadt.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/acpica/tbfadt.c b/drivers/acpi/acpica/tbfadt.c
index c5d8704..4c9c760 100644
--- a/drivers/acpi/acpica/tbfadt.c
+++ b/drivers/acpi/acpica/tbfadt.c
@@ -363,10 +363,6 @@ static void acpi_tb_convert_fadt(void)
 	u32 address32;
 	u32 i;
 
-	/* Update the local FADT table header length */
-
-	acpi_gbl_FADT.header.length = sizeof(struct acpi_table_fadt);
-
 	/*
 	 * Expand the 32-bit FACS and DSDT addresses to 64-bit as necessary.
 	 * Later code will always use the X 64-bit field. Also, check for an
@@ -408,6 +404,10 @@ static void acpi_tb_convert_fadt(void)
 		acpi_gbl_FADT.boot_flags = 0;
 	}
 
+	/* Update the local FADT table header length */
+
+	acpi_gbl_FADT.header.length = sizeof(struct acpi_table_fadt);
+
 	/*
 	 * Expand the ACPI 1.0 32-bit addresses to the ACPI 2.0 64-bit "X"
 	 * generic address structures as necessary. Later code will always use
-- 
1.7.3.4


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* RE: [PATCH] ACPICA: Fix regression in FADT revision checks
  2012-02-23 20:40 [PATCH] ACPICA: Fix regression in FADT revision checks Julian Anastasov
@ 2012-02-23 21:55 ` Moore, Robert
  2012-02-27 19:50 ` Len Brown
  1 sibling, 0 replies; 3+ messages in thread
From: Moore, Robert @ 2012-02-23 21:55 UTC (permalink / raw)
  To: Julian Anastasov, Len Brown; +Cc: linux-acpi

Julian,

We will make this change in ACPICA.

Bob


> -----Original Message-----
> From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-
> owner@vger.kernel.org] On Behalf Of Julian Anastasov
> Sent: Thursday, February 23, 2012 12:41 PM
> To: Len Brown
> Cc: linux-acpi@vger.kernel.org
> Subject: [PATCH] ACPICA: Fix regression in FADT revision checks
> 
> 	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.
> 
> Signed-off-by: Julian Anastasov <ja@ssi.bg>
> ---
>  drivers/acpi/acpica/tbfadt.c |    8 ++++----
>  1 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/acpi/acpica/tbfadt.c
> b/drivers/acpi/acpica/tbfadt.c
> index c5d8704..4c9c760 100644
> --- a/drivers/acpi/acpica/tbfadt.c
> +++ b/drivers/acpi/acpica/tbfadt.c
> @@ -363,10 +363,6 @@ static void acpi_tb_convert_fadt(void)
>  	u32 address32;
>  	u32 i;
> 
> -	/* Update the local FADT table header length */
> -
> -	acpi_gbl_FADT.header.length = sizeof(struct acpi_table_fadt);
> -
>  	/*
>  	 * Expand the 32-bit FACS and DSDT addresses to 64-bit as
> necessary.
>  	 * Later code will always use the X 64-bit field. Also, check for
> an
> @@ -408,6 +404,10 @@ static void acpi_tb_convert_fadt(void)
>  		acpi_gbl_FADT.boot_flags = 0;
>  	}
> 
> +	/* Update the local FADT table header length */
> +
> +	acpi_gbl_FADT.header.length = sizeof(struct acpi_table_fadt);
> +
>  	/*
>  	 * Expand the ACPI 1.0 32-bit addresses to the ACPI 2.0 64-bit
> "X"
>  	 * generic address structures as necessary. Later code will
> always use
> --
> 1.7.3.4
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-acpi"
> in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] ACPICA: Fix regression in FADT revision checks
  2012-02-23 20:40 [PATCH] ACPICA: Fix regression in FADT revision checks Julian Anastasov
  2012-02-23 21:55 ` Moore, Robert
@ 2012-02-27 19:50 ` Len Brown
  1 sibling, 0 replies; 3+ messages in thread
From: Len Brown @ 2012-02-27 19:50 UTC (permalink / raw)
  To: Julian Anastasov; +Cc: linux-acpi

Applied.
Nice find, Julian.

-Len Brown, Intel Open Source Technology Center

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2012-02-27 19:50 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2012-02-23 20:40 [PATCH] ACPICA: Fix regression in FADT revision checks Julian Anastasov
2012-02-23 21:55 ` Moore, Robert
2012-02-27 19:50 ` Len Brown

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