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Commit 96f15efc authored by Len Brown's avatar Len Brown
Browse files

ACPI: Disable _GTS and _BFS support by default 

Executing BIOS code paths not exercised by Windows
tends to get Linux into trouble.

However, if a system does benefit from _GTS or _BFS,
acpi.gts=1 an acpi.bfs=1 are now available to enable them.

http://bugzilla.kernel.org/show_bug.cgi?id=13041



Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent 0882e8dd

drivers/acpi/acpica/hwsleep.c

+26 −17
Original line number Diff line number Diff line
@@ -211,6 +211,12 @@ acpi_status acpi_enter_sleep_state_prep(u8 sleep_state) 


ACPI_EXPORT_SYMBOL(acpi_enter_sleep_state_prep)



static unsigned int gts, bfs;

module_param(gts, uint, 0644);

module_param(bfs, uint, 0644);

MODULE_PARM_DESC(gts, "Enable evaluation of _GTS on suspend.");

MODULE_PARM_DESC(bfs, "Enable evaluation of _BFS on resume".);



/*******************************************************************************

 *

 * FUNCTION:    acpi_enter_sleep_state
@@ -278,6 +284,7 @@ acpi_status asmlinkage acpi_enter_sleep_state(u8 sleep_state) 
		return_ACPI_STATUS(status);

	}



	if (gts) {

		/* Execute the _GTS method */



		arg_list.count = 1;
@@ -289,6 +296,7 @@ acpi_status asmlinkage acpi_enter_sleep_state(u8 sleep_state) 
		if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {

			return_ACPI_STATUS(status);

		}

	}



	/* Get current value of PM1A control */
@@ -513,6 +521,7 @@ acpi_status acpi_leave_sleep_state_prep(u8 sleep_state) 
		}

	}



	if (bfs) {

		/* Execute the _BFS method */



		arg_list.count = 1;
@@ -524,7 +533,7 @@ acpi_status acpi_leave_sleep_state_prep(u8 sleep_state) 
		if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {

			ACPI_EXCEPTION((AE_INFO, status, "During Method _BFS"));

		}



	}

	return_ACPI_STATUS(status);

}

drivers/acpi/sleep.c

+27 −0
Original line number Diff line number Diff line
@@ -713,6 +713,32 @@ static void acpi_power_off(void) 
	acpi_enter_sleep_state(ACPI_STATE_S5);

}



/*

 * ACPI 2.0 created the optional _GTS and _BFS,

 * but industry adoption has been neither rapid nor broad.

 *

 * Linux gets into trouble when it executes poorly validated

 * paths through the BIOS, so disable _GTS and _BFS by default,

 * but do speak up and offer the option to enable them.

 */

void __init acpi_gts_bfs_check(void)

{

	acpi_handle dummy;



	if (ACPI_SUCCESS(acpi_get_handle(ACPI_ROOT_OBJECT, METHOD_NAME__GTS, &dummy)))

	{

		printk(KERN_NOTICE PREFIX "BIOS offers _GTS\n");

		printk(KERN_NOTICE PREFIX "If \"acpi.gts=1\" improves suspend, "

			"please notify linux-acpi@vger.kernel.org\n");

	}

	if (ACPI_SUCCESS(acpi_get_handle(ACPI_ROOT_OBJECT, METHOD_NAME__BFS, &dummy)))

	{

		printk(KERN_NOTICE PREFIX "BIOS offers _BFS\n");

		printk(KERN_NOTICE PREFIX "If \"acpi.bfs=1\" improves resume, "

			"please notify linux-acpi@vger.kernel.org\n");

	}

}



int __init acpi_sleep_init(void)

{

	acpi_status status;
@@ -771,5 +797,6 @@ int __init acpi_sleep_init(void) 
	 * object can also be evaluated when the system enters S5.

	 */

	register_reboot_notifier(&tts_notifier);

	acpi_gts_bfs_check();

	return 0;

}