[PATCH 2/5] ACPI / ACPICA: Fix low-level GPE manipulation code

From: Rafael J. Wysocki
Date: Tue Jun 08 2010 - 05:01:51 EST

From: Rafael J. Wysocki <rjw@xxxxxxx>

ACPICA uses acpi_ev_enable_gpe() for enabling GPEs at the low level,
which is incorrect, because this function only enables the GPE if the
corresponding bit in its enable register's enable_for_run mask is set.
This causes acpi_set_gpe() to work incorrectly if used for enabling
GPEs that were not previously enabled with acpi_enable_gpe(). As a
result, among other things, wakeup-only GPEs are never enabled by
acpi_enable_wakeup_device(), so the devices that use them are unable
to wake up the system.

To fix this issue remove acpi_ev_enable_gpe() and its counterpart
acpi_ev_disable_gpe() and replace acpi_hw_low_disable_gpe() with
acpi_hw_low_set_gpe() that will be used instead to manipulate GPE
enable bits at the low level. Make the users of acpi_ev_enable_gpe()
and acpi_ev_disable_gpe() call acpi_hw_low_set_gpe() instead and
make sure that GPE enable masks are only updated by acpi_enable_gpe()
and acpi_disable_gpe() when GPE reference counters change from 0
to 1 and from 1 to 0, respectively.

Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
---
drivers/acpi/acpica/acevents.h | 4 -
drivers/acpi/acpica/achware.h | 3 -
drivers/acpi/acpica/evgpe.c | 108 -----------------------------------------
drivers/acpi/acpica/evxface.c | 2
drivers/acpi/acpica/evxfevnt.c | 59 ++++++++++++++++++++--
drivers/acpi/acpica/hwgpe.c | 26 +++++++--
include/acpi/actypes.h | 2
7 files changed, 80 insertions(+), 124 deletions(-)

Index: linux-2.6/drivers/acpi/acpica/hwgpe.c
===================================================================
--- linux-2.6.orig/drivers/acpi/acpica/hwgpe.c
+++ linux-2.6/drivers/acpi/acpica/hwgpe.c
@@ -78,23 +78,27 @@ u32 acpi_hw_gpe_register_bit(struct acpi

/******************************************************************************
*
- * FUNCTION: acpi_hw_low_disable_gpe
+ * FUNCTION: acpi_hw_low_set_gpe
*
* PARAMETERS: gpe_event_info - Info block for the GPE to be disabled
+ * action - Enable or disable
*
* RETURN: Status
*
- * DESCRIPTION: Disable a single GPE in the enable register.
+ * DESCRIPTION: Enable or disable a single GPE in its enable register.
*
******************************************************************************/

-acpi_status acpi_hw_low_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
+acpi_status
+acpi_hw_low_set_gpe(struct acpi_gpe_event_info *gpe_event_info, u8 action)
{
struct acpi_gpe_register_info *gpe_register_info;
acpi_status status;
u32 enable_mask;
u32 register_bit;

+ ACPI_FUNCTION_ENTRY();
+
/* Get the info block for the entire GPE register */

gpe_register_info = gpe_event_info->register_info;
@@ -109,11 +113,23 @@ acpi_status acpi_hw_low_disable_gpe(stru
return (status);
}

- /* Clear just the bit that corresponds to this GPE */
+ /* Set ot clear just the bit that corresponds to this GPE */

register_bit = acpi_hw_gpe_register_bit(gpe_event_info,
gpe_register_info);
- ACPI_CLEAR_BIT(enable_mask, register_bit);
+ switch (action) {
+ case ACPI_GPE_ENABLE:
+ ACPI_SET_BIT(enable_mask, register_bit);
+ break;
+
+ case ACPI_GPE_DISABLE:
+ ACPI_CLEAR_BIT(enable_mask, register_bit);
+ break;
+
+ default:
+ ACPI_ERROR((AE_INFO, "Invalid action\n"));
+ return (AE_BAD_PARAMETER);
+ }

/* Write the updated enable mask */

Index: linux-2.6/drivers/acpi/acpica/achware.h
===================================================================
--- linux-2.6.orig/drivers/acpi/acpica/achware.h
+++ linux-2.6/drivers/acpi/acpica/achware.h
@@ -93,7 +93,8 @@ acpi_status acpi_hw_write_port(acpi_io_a
u32 acpi_hw_gpe_register_bit(struct acpi_gpe_event_info *gpe_event_info,
struct acpi_gpe_register_info *gpe_register_info);

-acpi_status acpi_hw_low_disable_gpe(struct acpi_gpe_event_info *gpe_event_info);
+acpi_status
+acpi_hw_low_set_gpe(struct acpi_gpe_event_info *gpe_event_info, u8 action);

acpi_status
acpi_hw_write_gpe_enable_reg(struct acpi_gpe_event_info *gpe_event_info);
Index: linux-2.6/drivers/acpi/acpica/evgpe.c
===================================================================
--- linux-2.6.orig/drivers/acpi/acpica/evgpe.c
+++ linux-2.6/drivers/acpi/acpica/evgpe.c
@@ -99,106 +99,6 @@ acpi_ev_update_gpe_enable_masks(struct a
return_ACPI_STATUS(AE_OK);
}

-/*******************************************************************************
- *
- * FUNCTION: acpi_ev_enable_gpe
- *
- * PARAMETERS: gpe_event_info - GPE to enable
- *
- * RETURN: Status
- *
- * DESCRIPTION: Hardware-enable a GPE. Always enables the GPE, regardless
- * of type or number of references.
- *
- * Note: The GPE lock should be already acquired when this function is called.
- *
- ******************************************************************************/
-
-acpi_status acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info)
-{
- acpi_status status;
-
-
- ACPI_FUNCTION_TRACE(ev_enable_gpe);
-
-
- /*
- * We will only allow a GPE to be enabled if it has either an
- * associated method (_Lxx/_Exx) or a handler. Otherwise, the
- * GPE will be immediately disabled by acpi_ev_gpe_dispatch the
- * first time it fires.
- */
- if (!(gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK)) {
- return_ACPI_STATUS(AE_NO_HANDLER);
- }
-
- /* Ensure the HW enable masks are current */
-
- status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
- if (ACPI_FAILURE(status)) {
- return_ACPI_STATUS(status);
- }
-
- /* Clear the GPE (of stale events) */
-
- status = acpi_hw_clear_gpe(gpe_event_info);
- if (ACPI_FAILURE(status)) {
- return_ACPI_STATUS(status);
- }
-
- /* Enable the requested GPE */
-
- status = acpi_hw_write_gpe_enable_reg(gpe_event_info);
- return_ACPI_STATUS(status);
-}
-
-/*******************************************************************************
- *
- * FUNCTION: acpi_ev_disable_gpe
- *
- * PARAMETERS: gpe_event_info - GPE to disable
- *
- * RETURN: Status
- *
- * DESCRIPTION: Hardware-disable a GPE. Always disables the requested GPE,
- * regardless of the type or number of references.
- *
- * Note: The GPE lock should be already acquired when this function is called.
- *
- ******************************************************************************/
-
-acpi_status acpi_ev_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
-{
- acpi_status status;
-
- ACPI_FUNCTION_TRACE(ev_disable_gpe);
-
-
- /*
- * Note: Always disable the GPE, even if we think that that it is already
- * disabled. It is possible that the AML or some other code has enabled
- * the GPE behind our back.
- */
-
- /* Ensure the HW enable masks are current */
-
- status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
- if (ACPI_FAILURE(status)) {
- return_ACPI_STATUS(status);
- }
-
- /*
- * Always H/W disable this GPE, even if we don't know the GPE type.
- * Simply clear the enable bit for this particular GPE, but do not
- * write out the current GPE enable mask since this may inadvertently
- * enable GPEs too early. An example is a rogue GPE that has arrived
- * during ACPICA initialization - possibly because AML or other code
- * has enabled the GPE.
- */
- status = acpi_hw_low_disable_gpe(gpe_event_info);
- return_ACPI_STATUS(status);
-}
-

/*******************************************************************************
*
@@ -450,10 +350,6 @@ static void ACPI_SYSTEM_XFACE acpi_ev_as
return_VOID;
}

- /* Update the GPE register masks for return to enabled state */
-
- (void)acpi_ev_update_gpe_enable_masks(gpe_event_info);
-
/*
* Take a snapshot of the GPE info for this level - we copy the info to
* prevent a race condition with remove_handler/remove_block.
@@ -606,7 +502,7 @@ acpi_ev_gpe_dispatch(struct acpi_gpe_eve
* Disable the GPE, so it doesn't keep firing before the method has a
* chance to run (it runs asynchronously with interrupts enabled).
*/
- status = acpi_ev_disable_gpe(gpe_event_info);
+ status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_DISABLE);
if (ACPI_FAILURE(status)) {
ACPI_EXCEPTION((AE_INFO, status,
"Unable to disable GPE[0x%2X]",
@@ -643,7 +539,7 @@ acpi_ev_gpe_dispatch(struct acpi_gpe_eve
* Disable the GPE. The GPE will remain disabled a handler
* is installed or ACPICA is restarted.
*/
- status = acpi_ev_disable_gpe(gpe_event_info);
+ status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_DISABLE);
if (ACPI_FAILURE(status)) {
ACPI_EXCEPTION((AE_INFO, status,
"Unable to disable GPE[0x%2X]",
Index: linux-2.6/drivers/acpi/acpica/evxfevnt.c
===================================================================
--- linux-2.6.orig/drivers/acpi/acpica/evxfevnt.c
+++ linux-2.6/drivers/acpi/acpica/evxfevnt.c
@@ -210,6 +210,44 @@ ACPI_EXPORT_SYMBOL(acpi_enable_event)

/*******************************************************************************
*
+ * FUNCTION: acpi_clear_and_enable_gpe
+ *
+ * PARAMETERS: gpe_event_info - GPE to enable
+ *
+ * RETURN: Status
+ *
+ * DESCRIPTION: Clear the given GPE from stale events and enable it.
+ *
+ ******************************************************************************/
+static acpi_status
+acpi_clear_and_enable_gpe(struct acpi_gpe_event_info *gpe_event_info)
+{
+ acpi_status status;
+
+ /*
+ * We will only allow a GPE to be enabled if it has either an
+ * associated method (_Lxx/_Exx) or a handler. Otherwise, the
+ * GPE will be immediately disabled by acpi_ev_gpe_dispatch the
+ * first time it fires.
+ */
+ if (!(gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK)) {
+ return_ACPI_STATUS(AE_NO_HANDLER);
+ }
+
+ /* Clear the GPE (of stale events) */
+ status = acpi_hw_clear_gpe(gpe_event_info);
+ if (ACPI_FAILURE(status)) {
+ return_ACPI_STATUS(status);
+ }
+
+ /* Enable the requested GPE */
+ status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_ENABLE);
+
+ return_ACPI_STATUS(status);
+}
+
+/*******************************************************************************
+ *
* FUNCTION: acpi_set_gpe
*
* PARAMETERS: gpe_device - Parent GPE Device. NULL for GPE0/GPE1
@@ -249,11 +287,11 @@ acpi_status acpi_set_gpe(acpi_handle gpe

switch (action) {
case ACPI_GPE_ENABLE:
- status = acpi_ev_enable_gpe(gpe_event_info);
+ status = acpi_clear_and_enable_gpe(gpe_event_info);
break;

case ACPI_GPE_DISABLE:
- status = acpi_ev_disable_gpe(gpe_event_info);
+ status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_DISABLE);
break;

default:
@@ -316,7 +354,11 @@ acpi_status acpi_enable_gpe(acpi_handle

gpe_event_info->runtime_count++;
if (gpe_event_info->runtime_count == 1) {
- status = acpi_ev_enable_gpe(gpe_event_info);
+ status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
+ if (ACPI_SUCCESS(status)) {
+ status = acpi_clear_and_enable_gpe(gpe_event_info);
+ }
+
if (ACPI_FAILURE(status)) {
gpe_event_info->runtime_count--;
goto unlock_and_exit;
@@ -343,7 +385,7 @@ acpi_status acpi_enable_gpe(acpi_handle
*/
gpe_event_info->wakeup_count++;
if (gpe_event_info->wakeup_count == 1) {
- (void)acpi_ev_update_gpe_enable_masks(gpe_event_info);
+ status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
}
}

@@ -403,7 +445,12 @@ acpi_status acpi_disable_gpe(acpi_handle

gpe_event_info->runtime_count--;
if (!gpe_event_info->runtime_count) {
- status = acpi_ev_disable_gpe(gpe_event_info);
+ status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
+ if (ACPI_SUCCESS(status)) {
+ status = acpi_hw_low_set_gpe(gpe_event_info,
+ ACPI_GPE_DISABLE);
+ }
+
if (ACPI_FAILURE(status)) {
gpe_event_info->runtime_count++;
goto unlock_and_exit;
@@ -424,7 +471,7 @@ acpi_status acpi_disable_gpe(acpi_handle

gpe_event_info->wakeup_count--;
if (!gpe_event_info->wakeup_count) {
- (void)acpi_ev_update_gpe_enable_masks(gpe_event_info);
+ status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
}
}

Index: linux-2.6/include/acpi/actypes.h
===================================================================
--- linux-2.6.orig/include/acpi/actypes.h
+++ linux-2.6/include/acpi/actypes.h
@@ -663,7 +663,7 @@ typedef u32 acpi_event_status;
#define ACPI_GPE_MAX 0xFF
#define ACPI_NUM_GPE 256

-/* Actions for acpi_set_gpe */
+/* Actions for acpi_set_gpe and acpi_hw_low_set_gpe */

#define ACPI_GPE_ENABLE 0
#define ACPI_GPE_DISABLE 1
Index: linux-2.6/drivers/acpi/acpica/acevents.h
===================================================================
--- linux-2.6.orig/drivers/acpi/acpica/acevents.h
+++ linux-2.6/drivers/acpi/acpica/acevents.h
@@ -80,10 +80,6 @@ u32 acpi_ev_gpe_detect(struct acpi_gpe_x
acpi_status
acpi_ev_update_gpe_enable_masks(struct acpi_gpe_event_info *gpe_event_info);

-acpi_status acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info);
-
-acpi_status acpi_ev_disable_gpe(struct acpi_gpe_event_info *gpe_event_info);
-
struct acpi_gpe_event_info *acpi_ev_get_gpe_event_info(acpi_handle gpe_device,
u32 gpe_number);

Index: linux-2.6/drivers/acpi/acpica/evxface.c
===================================================================
--- linux-2.6.orig/drivers/acpi/acpica/evxface.c
+++ linux-2.6/drivers/acpi/acpica/evxface.c
@@ -721,7 +721,7 @@ acpi_install_gpe_handler(acpi_handle gpe

/* Disable the GPE before installing the handler */

- status = acpi_ev_disable_gpe(gpe_event_info);
+ status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_DISABLE);
if (ACPI_FAILURE (status)) {
goto unlock_and_exit;
}

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