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ACPI: delete _GTS/_BFS support
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_GTS and _BFS were added to the suspend/resume flow
in the ACPI 2.0 specification.

Linux dutifully implemented _GTS and _BFS.
We discovered that it was rarely seen in systems
in the field.  Further, some of those systems had
AML so bogus that it could never work -- proof that
no other operating system supports _GTS and _BFS.
So we made _GTS and _BFS optional via modparam,
and disabled them by default.

But we've had to complicate some code to keep
this support in the kernel, as these methods are defined
to be evaluated very close to sleep entry and exit.
Indeed, no other AML is ever evaluated with interrupts off.

We have submitted a proposal for _GTS and _BFS
to be officially removed from the ACPI specification
on the next revision.  Here we remove it from Linux.

Signed-off-by: Len Brown <len.brown@intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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Len Brown committed Jul 31, 2012
1 parent 3b6961b commit 3f6f49c
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Showing 7 changed files with 34 additions and 118 deletions.
12 changes: 6 additions & 6 deletions drivers/acpi/acpica/achware.h
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Original file line number Diff line number Diff line change
Expand Up @@ -83,22 +83,22 @@ acpi_status acpi_hw_clear_acpi_status(void);
/*
* hwsleep - sleep/wake support (Legacy sleep registers)
*/
acpi_status acpi_hw_legacy_sleep(u8 sleep_state, u8 flags);
acpi_status acpi_hw_legacy_sleep(u8 sleep_state);

acpi_status acpi_hw_legacy_wake_prep(u8 sleep_state, u8 flags);
acpi_status acpi_hw_legacy_wake_prep(u8 sleep_state);

acpi_status acpi_hw_legacy_wake(u8 sleep_state, u8 flags);
acpi_status acpi_hw_legacy_wake(u8 sleep_state);

/*
* hwesleep - sleep/wake support (Extended FADT-V5 sleep registers)
*/
void acpi_hw_execute_sleep_method(char *method_name, u32 integer_argument);

acpi_status acpi_hw_extended_sleep(u8 sleep_state, u8 flags);
acpi_status acpi_hw_extended_sleep(u8 sleep_state);

acpi_status acpi_hw_extended_wake_prep(u8 sleep_state, u8 flags);
acpi_status acpi_hw_extended_wake_prep(u8 sleep_state);

acpi_status acpi_hw_extended_wake(u8 sleep_state, u8 flags);
acpi_status acpi_hw_extended_wake(u8 sleep_state);

/*
* hwvalid - Port I/O with validation
Expand Down
19 changes: 3 additions & 16 deletions drivers/acpi/acpica/hwesleep.c
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Original file line number Diff line number Diff line change
Expand Up @@ -90,7 +90,6 @@ void acpi_hw_execute_sleep_method(char *method_pathname, u32 integer_argument)
* FUNCTION: acpi_hw_extended_sleep
*
* PARAMETERS: sleep_state - Which sleep state to enter
* flags - ACPI_EXECUTE_GTS to run optional method
*
* RETURN: Status
*
Expand All @@ -100,7 +99,7 @@ void acpi_hw_execute_sleep_method(char *method_pathname, u32 integer_argument)
*
******************************************************************************/

acpi_status acpi_hw_extended_sleep(u8 sleep_state, u8 flags)
acpi_status acpi_hw_extended_sleep(u8 sleep_state)
{
acpi_status status;
u8 sleep_type_value;
Expand All @@ -125,12 +124,6 @@ acpi_status acpi_hw_extended_sleep(u8 sleep_state, u8 flags)

acpi_gbl_system_awake_and_running = FALSE;

/* Optionally execute _GTS (Going To Sleep) */

if (flags & ACPI_EXECUTE_GTS) {
acpi_hw_execute_sleep_method(METHOD_PATHNAME__GTS, sleep_state);
}

/* Flush caches, as per ACPI specification */

ACPI_FLUSH_CPU_CACHE();
Expand Down Expand Up @@ -172,7 +165,6 @@ acpi_status acpi_hw_extended_sleep(u8 sleep_state, u8 flags)
* FUNCTION: acpi_hw_extended_wake_prep
*
* PARAMETERS: sleep_state - Which sleep state we just exited
* flags - ACPI_EXECUTE_BFS to run optional method
*
* RETURN: Status
*
Expand All @@ -181,7 +173,7 @@ acpi_status acpi_hw_extended_sleep(u8 sleep_state, u8 flags)
*
******************************************************************************/

acpi_status acpi_hw_extended_wake_prep(u8 sleep_state, u8 flags)
acpi_status acpi_hw_extended_wake_prep(u8 sleep_state)
{
acpi_status status;
u8 sleep_type_value;
Expand All @@ -200,11 +192,6 @@ acpi_status acpi_hw_extended_wake_prep(u8 sleep_state, u8 flags)
&acpi_gbl_FADT.sleep_control);
}

/* Optionally execute _BFS (Back From Sleep) */

if (flags & ACPI_EXECUTE_BFS) {
acpi_hw_execute_sleep_method(METHOD_PATHNAME__BFS, sleep_state);
}
return_ACPI_STATUS(AE_OK);
}

Expand All @@ -222,7 +209,7 @@ acpi_status acpi_hw_extended_wake_prep(u8 sleep_state, u8 flags)
*
******************************************************************************/

acpi_status acpi_hw_extended_wake(u8 sleep_state, u8 flags)
acpi_status acpi_hw_extended_wake(u8 sleep_state)
{
ACPI_FUNCTION_TRACE(hw_extended_wake);

Expand Down
20 changes: 3 additions & 17 deletions drivers/acpi/acpica/hwsleep.c
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Original file line number Diff line number Diff line change
Expand Up @@ -56,15 +56,14 @@ ACPI_MODULE_NAME("hwsleep")
* FUNCTION: acpi_hw_legacy_sleep
*
* PARAMETERS: sleep_state - Which sleep state to enter
* flags - ACPI_EXECUTE_GTS to run optional method
*
* RETURN: Status
*
* DESCRIPTION: Enter a system sleep state via the legacy FADT PM registers
* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED
*
******************************************************************************/
acpi_status acpi_hw_legacy_sleep(u8 sleep_state, u8 flags)
acpi_status acpi_hw_legacy_sleep(u8 sleep_state)
{
struct acpi_bit_register_info *sleep_type_reg_info;
struct acpi_bit_register_info *sleep_enable_reg_info;
Expand Down Expand Up @@ -110,12 +109,6 @@ acpi_status acpi_hw_legacy_sleep(u8 sleep_state, u8 flags)
return_ACPI_STATUS(status);
}

/* Optionally execute _GTS (Going To Sleep) */

if (flags & ACPI_EXECUTE_GTS) {
acpi_hw_execute_sleep_method(METHOD_PATHNAME__GTS, sleep_state);
}

/* Get current value of PM1A control */

status = acpi_hw_register_read(ACPI_REGISTER_PM1_CONTROL,
Expand Down Expand Up @@ -214,7 +207,6 @@ acpi_status acpi_hw_legacy_sleep(u8 sleep_state, u8 flags)
* FUNCTION: acpi_hw_legacy_wake_prep
*
* PARAMETERS: sleep_state - Which sleep state we just exited
* flags - ACPI_EXECUTE_BFS to run optional method
*
* RETURN: Status
*
Expand All @@ -224,7 +216,7 @@ acpi_status acpi_hw_legacy_sleep(u8 sleep_state, u8 flags)
*
******************************************************************************/

acpi_status acpi_hw_legacy_wake_prep(u8 sleep_state, u8 flags)
acpi_status acpi_hw_legacy_wake_prep(u8 sleep_state)
{
acpi_status status;
struct acpi_bit_register_info *sleep_type_reg_info;
Expand Down Expand Up @@ -275,11 +267,6 @@ acpi_status acpi_hw_legacy_wake_prep(u8 sleep_state, u8 flags)
}
}

/* Optionally execute _BFS (Back From Sleep) */

if (flags & ACPI_EXECUTE_BFS) {
acpi_hw_execute_sleep_method(METHOD_PATHNAME__BFS, sleep_state);
}
return_ACPI_STATUS(status);
}

Expand All @@ -288,7 +275,6 @@ acpi_status acpi_hw_legacy_wake_prep(u8 sleep_state, u8 flags)
* FUNCTION: acpi_hw_legacy_wake
*
* PARAMETERS: sleep_state - Which sleep state we just exited
* flags - Reserved, set to zero
*
* RETURN: Status
*
Expand All @@ -297,7 +283,7 @@ acpi_status acpi_hw_legacy_wake_prep(u8 sleep_state, u8 flags)
*
******************************************************************************/

acpi_status acpi_hw_legacy_wake(u8 sleep_state, u8 flags)
acpi_status acpi_hw_legacy_wake(u8 sleep_state)
{
acpi_status status;

Expand Down
22 changes: 10 additions & 12 deletions drivers/acpi/acpica/hwxfsleep.c
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Original file line number Diff line number Diff line change
Expand Up @@ -50,7 +50,7 @@ ACPI_MODULE_NAME("hwxfsleep")

/* Local prototypes */
static acpi_status
acpi_hw_sleep_dispatch(u8 sleep_state, u8 flags, u32 function_id);
acpi_hw_sleep_dispatch(u8 sleep_state, u32 function_id);

/*
* Dispatch table used to efficiently branch to the various sleep
Expand Down Expand Up @@ -235,7 +235,7 @@ ACPI_EXPORT_SYMBOL(acpi_enter_sleep_state_s4bios)
*
******************************************************************************/
static acpi_status
acpi_hw_sleep_dispatch(u8 sleep_state, u8 flags, u32 function_id)
acpi_hw_sleep_dispatch(u8 sleep_state, u32 function_id)
{
acpi_status status;
struct acpi_sleep_functions *sleep_functions =
Expand All @@ -248,11 +248,11 @@ acpi_hw_sleep_dispatch(u8 sleep_state, u8 flags, u32 function_id)
* use the extended sleep registers
*/
if (acpi_gbl_reduced_hardware || acpi_gbl_FADT.sleep_control.address) {
status = sleep_functions->extended_function(sleep_state, flags);
status = sleep_functions->extended_function(sleep_state);
} else {
/* Legacy sleep */

status = sleep_functions->legacy_function(sleep_state, flags);
status = sleep_functions->legacy_function(sleep_state);
}

return (status);
Expand All @@ -262,7 +262,7 @@ acpi_hw_sleep_dispatch(u8 sleep_state, u8 flags, u32 function_id)
* For the case where reduced-hardware-only code is being generated,
* we know that only the extended sleep registers are available
*/
status = sleep_functions->extended_function(sleep_state, flags);
status = sleep_functions->extended_function(sleep_state);
return (status);

#endif /* !ACPI_REDUCED_HARDWARE */
Expand Down Expand Up @@ -349,15 +349,14 @@ ACPI_EXPORT_SYMBOL(acpi_enter_sleep_state_prep)
* FUNCTION: acpi_enter_sleep_state
*
* PARAMETERS: sleep_state - Which sleep state to enter
* flags - ACPI_EXECUTE_GTS to run optional method
*
* RETURN: Status
*
* DESCRIPTION: Enter a system sleep state (see ACPI 2.0 spec p 231)
* THIS FUNCTION MUST BE CALLED WITH INTERRUPTS DISABLED
*
******************************************************************************/
acpi_status asmlinkage acpi_enter_sleep_state(u8 sleep_state, u8 flags)
acpi_status asmlinkage acpi_enter_sleep_state(u8 sleep_state)
{
acpi_status status;

Expand All @@ -371,7 +370,7 @@ acpi_status asmlinkage acpi_enter_sleep_state(u8 sleep_state, u8 flags)
}

status =
acpi_hw_sleep_dispatch(sleep_state, flags, ACPI_SLEEP_FUNCTION_ID);
acpi_hw_sleep_dispatch(sleep_state, ACPI_SLEEP_FUNCTION_ID);
return_ACPI_STATUS(status);
}

Expand All @@ -391,14 +390,14 @@ ACPI_EXPORT_SYMBOL(acpi_enter_sleep_state)
* Called with interrupts DISABLED.
*
******************************************************************************/
acpi_status acpi_leave_sleep_state_prep(u8 sleep_state, u8 flags)
acpi_status acpi_leave_sleep_state_prep(u8 sleep_state)
{
acpi_status status;

ACPI_FUNCTION_TRACE(acpi_leave_sleep_state_prep);

status =
acpi_hw_sleep_dispatch(sleep_state, flags,
acpi_hw_sleep_dispatch(sleep_state,
ACPI_WAKE_PREP_FUNCTION_ID);
return_ACPI_STATUS(status);
}
Expand All @@ -423,8 +422,7 @@ acpi_status acpi_leave_sleep_state(u8 sleep_state)

ACPI_FUNCTION_TRACE(acpi_leave_sleep_state);


status = acpi_hw_sleep_dispatch(sleep_state, 0, ACPI_WAKE_FUNCTION_ID);
status = acpi_hw_sleep_dispatch(sleep_state, ACPI_WAKE_FUNCTION_ID);
return_ACPI_STATUS(status);
}

Expand Down
73 changes: 9 additions & 64 deletions drivers/acpi/sleep.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -28,34 +28,6 @@
#include "internal.h"
#include "sleep.h"

u8 wake_sleep_flags = ACPI_NO_OPTIONAL_METHODS;
static unsigned int gts, bfs;
static int set_param_wake_flag(const char *val, struct kernel_param *kp)
{
int ret = param_set_int(val, kp);

if (ret)
return ret;

if (kp->arg == (const char *)&gts) {
if (gts)
wake_sleep_flags |= ACPI_EXECUTE_GTS;
else
wake_sleep_flags &= ~ACPI_EXECUTE_GTS;
}
if (kp->arg == (const char *)&bfs) {
if (bfs)
wake_sleep_flags |= ACPI_EXECUTE_BFS;
else
wake_sleep_flags &= ~ACPI_EXECUTE_BFS;
}
return ret;
}
module_param_call(gts, set_param_wake_flag, param_get_int, &gts, 0644);
module_param_call(bfs, set_param_wake_flag, param_get_int, &bfs, 0644);
MODULE_PARM_DESC(gts, "Enable evaluation of _GTS on suspend.");
MODULE_PARM_DESC(bfs, "Enable evaluation of _BFS on resume".);

static u8 sleep_states[ACPI_S_STATE_COUNT];
static bool pwr_btn_event_pending;

Expand Down Expand Up @@ -305,7 +277,7 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
switch (acpi_state) {
case ACPI_STATE_S1:
barrier();
status = acpi_enter_sleep_state(acpi_state, wake_sleep_flags);
status = acpi_enter_sleep_state(acpi_state);
break;

case ACPI_STATE_S3:
Expand All @@ -319,8 +291,8 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
/* This violates the spec but is required for bug compatibility. */
acpi_write_bit_register(ACPI_BITREG_SCI_ENABLE, 1);

/* Reprogram control registers and execute _BFS */
acpi_leave_sleep_state_prep(acpi_state, wake_sleep_flags);
/* Reprogram control registers */
acpi_leave_sleep_state_prep(acpi_state);

/* ACPI 3.0 specs (P62) says that it's the responsibility
* of the OSPM to clear the status bit [ implying that the
Expand Down Expand Up @@ -603,9 +575,9 @@ static int acpi_hibernation_enter(void)
ACPI_FLUSH_CPU_CACHE();

/* This shouldn't return. If it returns, we have a problem */
status = acpi_enter_sleep_state(ACPI_STATE_S4, wake_sleep_flags);
/* Reprogram control registers and execute _BFS */
acpi_leave_sleep_state_prep(ACPI_STATE_S4, wake_sleep_flags);
status = acpi_enter_sleep_state(ACPI_STATE_S4);
/* Reprogram control registers */
acpi_leave_sleep_state_prep(ACPI_STATE_S4);

return ACPI_SUCCESS(status) ? 0 : -EFAULT;
}
Expand All @@ -617,8 +589,8 @@ static void acpi_hibernation_leave(void)
* enable it here.
*/
acpi_enable();
/* Reprogram control registers and execute _BFS */
acpi_leave_sleep_state_prep(ACPI_STATE_S4, wake_sleep_flags);
/* Reprogram control registers */
acpi_leave_sleep_state_prep(ACPI_STATE_S4);
/* Check the hardware signature */
if (facs && s4_hardware_signature != facs->hardware_signature) {
printk(KERN_EMERG "ACPI: Hardware changed while hibernated, "
Expand Down Expand Up @@ -876,33 +848,7 @@ static void acpi_power_off(void)
/* acpi_sleep_prepare(ACPI_STATE_S5) should have already been called */
printk(KERN_DEBUG "%s called\n", __func__);
local_irq_disable();
acpi_enter_sleep_state(ACPI_STATE_S5, wake_sleep_flags);
}

/*
* 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.
*/
static void __init acpi_gts_bfs_check(void)
{
acpi_handle dummy;

if (ACPI_SUCCESS(acpi_get_handle(ACPI_ROOT_OBJECT, METHOD_PATHNAME__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_PATHNAME__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");
}
acpi_enter_sleep_state(ACPI_STATE_S5);
}

int __init acpi_sleep_init(void)
Expand Down Expand Up @@ -963,6 +909,5 @@ 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;
}
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