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-rw-r--r--drivers/acpi/ec.c390
1 files changed, 276 insertions, 114 deletions
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index fdf143b405be..69b04d430f00 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -31,6 +31,7 @@
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
+#include <linux/interrupt.h>
#include <asm/io.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
@@ -49,17 +50,19 @@ ACPI_MODULE_NAME ("acpi_ec")
#define ACPI_EC_FLAG_OBF 0x01 /* Output buffer full */
#define ACPI_EC_FLAG_IBF 0x02 /* Input buffer full */
+#define ACPI_EC_FLAG_BURST 0x10 /* burst mode */
#define ACPI_EC_FLAG_SCI 0x20 /* EC-SCI occurred */
#define ACPI_EC_EVENT_OBF 0x01 /* Output buffer full */
#define ACPI_EC_EVENT_IBE 0x02 /* Input buffer empty */
-#define ACPI_EC_UDELAY 100 /* Poll @ 100us increments */
-#define ACPI_EC_UDELAY_COUNT 1000 /* Wait 10ms max. during EC ops */
+#define ACPI_EC_DELAY 50 /* Wait 50ms max. during EC ops */
#define ACPI_EC_UDELAY_GLK 1000 /* Wait 1ms max. to get global lock */
#define ACPI_EC_COMMAND_READ 0x80
#define ACPI_EC_COMMAND_WRITE 0x81
+#define ACPI_EC_BURST_ENABLE 0x82
+#define ACPI_EC_BURST_DISABLE 0x83
#define ACPI_EC_COMMAND_QUERY 0x84
static int acpi_ec_add (struct acpi_device *device);
@@ -87,7 +90,11 @@ struct acpi_ec {
struct acpi_generic_address command_addr;
struct acpi_generic_address data_addr;
unsigned long global_lock;
- spinlock_t lock;
+ unsigned int expect_event;
+ atomic_t leaving_burst; /* 0 : No, 1 : Yes, 2: abort*/
+ atomic_t pending_gpe;
+ struct semaphore sem;
+ wait_queue_head_t wait;
};
/* If we find an EC via the ECDT, we need to keep a ptr to its context */
@@ -100,59 +107,138 @@ static struct acpi_device *first_ec;
Transaction Management
-------------------------------------------------------------------------- */
-static int
-acpi_ec_wait (
- struct acpi_ec *ec,
- u8 event)
+static inline u32 acpi_ec_read_status(struct acpi_ec *ec)
{
- u32 acpi_ec_status = 0;
- u32 i = ACPI_EC_UDELAY_COUNT;
+ u32 status = 0;
- if (!ec)
- return -EINVAL;
+ acpi_hw_low_level_read(8, &status, &ec->status_addr);
+ return status;
+}
+
+static int acpi_ec_wait(struct acpi_ec *ec, unsigned int event)
+{
+ int result = 0;
+
+ ACPI_FUNCTION_TRACE("acpi_ec_wait");
- /* Poll the EC status register waiting for the event to occur. */
+ ec->expect_event = event;
+ smp_mb();
+
+ result = wait_event_interruptible_timeout(ec->wait,
+ !ec->expect_event,
+ msecs_to_jiffies(ACPI_EC_DELAY));
+
+ ec->expect_event = 0;
+ smp_mb();
+
+ if (result < 0){
+ ACPI_DEBUG_PRINT((ACPI_DB_ERROR," result = %d ", result));
+ return_VALUE(result);
+ }
+
+ /*
+ * Verify that the event in question has actually happened by
+ * querying EC status. Do the check even if operation timed-out
+ * to make sure that we did not miss interrupt.
+ */
switch (event) {
case ACPI_EC_EVENT_OBF:
- do {
- acpi_hw_low_level_read(8, &acpi_ec_status, &ec->status_addr);
- if (acpi_ec_status & ACPI_EC_FLAG_OBF)
- return 0;
- udelay(ACPI_EC_UDELAY);
- } while (--i>0);
+ if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_OBF)
+ return_VALUE(0);
break;
+
case ACPI_EC_EVENT_IBE:
- do {
- acpi_hw_low_level_read(8, &acpi_ec_status, &ec->status_addr);
- if (!(acpi_ec_status & ACPI_EC_FLAG_IBF))
- return 0;
- udelay(ACPI_EC_UDELAY);
- } while (--i>0);
+ if (~acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF)
+ return_VALUE(0);
break;
- default:
- return -EINVAL;
}
- return -ETIME;
+ return_VALUE(-ETIME);
}
+
+static int
+acpi_ec_enter_burst_mode (
+ struct acpi_ec *ec)
+{
+ u32 tmp = 0;
+ int status = 0;
+
+ ACPI_FUNCTION_TRACE("acpi_ec_enter_burst_mode");
+
+ status = acpi_ec_read_status(ec);
+ if (status != -EINVAL &&
+ !(status & ACPI_EC_FLAG_BURST)){
+ ACPI_DEBUG_PRINT((ACPI_DB_INFO,"entering burst mode \n"));
+ acpi_hw_low_level_write(8, ACPI_EC_BURST_ENABLE, &ec->command_addr);
+ status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
+ if (status){
+ acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+ ACPI_DEBUG_PRINT((ACPI_DB_ERROR," status = %d\n", status));
+ return_VALUE(-EINVAL);
+ }
+ acpi_hw_low_level_read(8, &tmp, &ec->data_addr);
+ acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+ if(tmp != 0x90 ) {/* Burst ACK byte*/
+ ACPI_DEBUG_PRINT((ACPI_DB_ERROR,"Ack failed \n"));
+ return_VALUE(-EINVAL);
+ }
+ } else
+ ACPI_DEBUG_PRINT((ACPI_DB_INFO,"already be in burst mode \n"));
+ atomic_set(&ec->leaving_burst , 0);
+ return_VALUE(0);
+}
+
+static int
+acpi_ec_leave_burst_mode (
+ struct acpi_ec *ec)
+{
+ int status =0;
+
+ ACPI_FUNCTION_TRACE("acpi_ec_leave_burst_mode");
+
+ atomic_set(&ec->leaving_burst , 1);
+ status = acpi_ec_read_status(ec);
+ if (status != -EINVAL &&
+ (status & ACPI_EC_FLAG_BURST)){
+ ACPI_DEBUG_PRINT((ACPI_DB_INFO,"leaving burst mode\n"));
+ acpi_hw_low_level_write(8, ACPI_EC_BURST_DISABLE, &ec->command_addr);
+ status = acpi_ec_wait(ec, ACPI_EC_FLAG_IBF);
+ if (status){
+ acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+ ACPI_DEBUG_PRINT((ACPI_DB_ERROR,"------->wait fail\n"));
+ return_VALUE(-EINVAL);
+ }
+ acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+ status = acpi_ec_read_status(ec);
+ if (status != -EINVAL &&
+ (status & ACPI_EC_FLAG_BURST)) {
+ ACPI_DEBUG_PRINT((ACPI_DB_ERROR,"------->status fail\n"));
+ return_VALUE(-EINVAL);
+ }
+ }else
+ ACPI_DEBUG_PRINT((ACPI_DB_INFO,"already be in Non-burst mode \n"));
+ ACPI_DEBUG_PRINT((ACPI_DB_INFO,"leaving burst mode\n"));
+
+ return_VALUE(0);
+}
+
static int
acpi_ec_read (
struct acpi_ec *ec,
u8 address,
u32 *data)
{
- acpi_status status = AE_OK;
- int result = 0;
- unsigned long flags = 0;
- u32 glk = 0;
+ int status = 0;
+ u32 glk;
ACPI_FUNCTION_TRACE("acpi_ec_read");
if (!ec || !data)
return_VALUE(-EINVAL);
+retry:
*data = 0;
if (ec->global_lock) {
@@ -160,32 +246,50 @@ acpi_ec_read (
if (ACPI_FAILURE(status))
return_VALUE(-ENODEV);
}
-
- spin_lock_irqsave(&ec->lock, flags);
+
+ WARN_ON(in_interrupt());
+ down(&ec->sem);
+
+ if(acpi_ec_enter_burst_mode(ec))
+ goto end;
acpi_hw_low_level_write(8, ACPI_EC_COMMAND_READ, &ec->command_addr);
- result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
- if (result)
+ status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+ acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+ if (status) {
goto end;
+ }
acpi_hw_low_level_write(8, address, &ec->data_addr);
- result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
- if (result)
+ status= acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
+ if (status){
+ acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
goto end;
-
+ }
acpi_hw_low_level_read(8, data, &ec->data_addr);
+ acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Read [%02x] from address [%02x]\n",
*data, address));
-
+
end:
- spin_unlock_irqrestore(&ec->lock, flags);
+ acpi_ec_leave_burst_mode(ec);
+ up(&ec->sem);
if (ec->global_lock)
acpi_release_global_lock(glk);
- return_VALUE(result);
+ if(atomic_read(&ec->leaving_burst) == 2){
+ ACPI_DEBUG_PRINT((ACPI_DB_INFO,"aborted, retry ...\n"));
+ while(!atomic_read(&ec->pending_gpe)){
+ msleep(1);
+ }
+ acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+ goto retry;
+ }
+
+ return_VALUE(status);
}
@@ -195,49 +299,80 @@ acpi_ec_write (
u8 address,
u8 data)
{
- int result = 0;
- acpi_status status = AE_OK;
- unsigned long flags = 0;
- u32 glk = 0;
+ int status = 0;
+ u32 glk;
+ u32 tmp;
ACPI_FUNCTION_TRACE("acpi_ec_write");
if (!ec)
return_VALUE(-EINVAL);
-
+retry:
if (ec->global_lock) {
status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
if (ACPI_FAILURE(status))
return_VALUE(-ENODEV);
}
- spin_lock_irqsave(&ec->lock, flags);
+ WARN_ON(in_interrupt());
+ down(&ec->sem);
+
+ if(acpi_ec_enter_burst_mode(ec))
+ goto end;
+
+ status = acpi_ec_read_status(ec);
+ if (status != -EINVAL &&
+ !(status & ACPI_EC_FLAG_BURST)){
+ acpi_hw_low_level_write(8, ACPI_EC_BURST_ENABLE, &ec->command_addr);
+ status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
+ if (status)
+ goto end;
+ acpi_hw_low_level_read(8, &tmp, &ec->data_addr);
+ if(tmp != 0x90 ) /* Burst ACK byte*/
+ goto end;
+ }
+ /*Now we are in burst mode*/
acpi_hw_low_level_write(8, ACPI_EC_COMMAND_WRITE, &ec->command_addr);
- result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
- if (result)
+ status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+ acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+ if (status){
goto end;
+ }
acpi_hw_low_level_write(8, address, &ec->data_addr);
- result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
- if (result)
+ status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+ if (status){
+ acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
goto end;
+ }
acpi_hw_low_level_write(8, data, &ec->data_addr);
- result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
- if (result)
+ status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
+ acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+ if (status)
goto end;
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Wrote [%02x] to address [%02x]\n",
data, address));
end:
- spin_unlock_irqrestore(&ec->lock, flags);
+ acpi_ec_leave_burst_mode(ec);
+ up(&ec->sem);
if (ec->global_lock)
acpi_release_global_lock(glk);
- return_VALUE(result);
+ if(atomic_read(&ec->leaving_burst) == 2){
+ ACPI_DEBUG_PRINT((ACPI_DB_INFO,"aborted, retry ...\n"));
+ while(!atomic_read(&ec->pending_gpe)){
+ msleep(1);
+ }
+ acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+ goto retry;
+ }
+
+ return_VALUE(status);
}
/*
@@ -289,16 +424,14 @@ acpi_ec_query (
struct acpi_ec *ec,
u32 *data)
{
- int result = 0;
- acpi_status status = AE_OK;
- unsigned long flags = 0;
- u32 glk = 0;
+ int status = 0;
+ u32 glk;
ACPI_FUNCTION_TRACE("acpi_ec_query");
if (!ec || !data)
return_VALUE(-EINVAL);
-
+retry:
*data = 0;
if (ec->global_lock) {
@@ -307,29 +440,43 @@ acpi_ec_query (
return_VALUE(-ENODEV);
}
+ down(&ec->sem);
+ if(acpi_ec_enter_burst_mode(ec))
+ goto end;
/*
* Query the EC to find out which _Qxx method we need to evaluate.
* Note that successful completion of the query causes the ACPI_EC_SCI
* bit to be cleared (and thus clearing the interrupt source).
*/
- spin_lock_irqsave(&ec->lock, flags);
-
acpi_hw_low_level_write(8, ACPI_EC_COMMAND_QUERY, &ec->command_addr);
- result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
- if (result)
+ status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
+ if (status){
+ acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
goto end;
-
+ }
+
acpi_hw_low_level_read(8, data, &ec->data_addr);
+ acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
if (!*data)
- result = -ENODATA;
+ status = -ENODATA;
end:
- spin_unlock_irqrestore(&ec->lock, flags);
+ acpi_ec_leave_burst_mode(ec);
+ up(&ec->sem);
if (ec->global_lock)
acpi_release_global_lock(glk);
- return_VALUE(result);
+ if(atomic_read(&ec->leaving_burst) == 2){
+ ACPI_DEBUG_PRINT((ACPI_DB_INFO,"aborted, retry ...\n"));
+ while(!atomic_read(&ec->pending_gpe)){
+ msleep(1);
+ }
+ acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+ goto retry;
+ }
+
+ return_VALUE(status);
}
@@ -347,42 +494,29 @@ acpi_ec_gpe_query (
void *ec_cxt)
{
struct acpi_ec *ec = (struct acpi_ec *) ec_cxt;
- u32 value = 0;
- unsigned long flags = 0;
+ u32 value;
+ int result = -ENODATA;
static char object_name[5] = {'_','Q','0','0','\0'};
const char hex[] = {'0','1','2','3','4','5','6','7',
'8','9','A','B','C','D','E','F'};
ACPI_FUNCTION_TRACE("acpi_ec_gpe_query");
- if (!ec_cxt)
- goto end;
+ if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_SCI)
+ result = acpi_ec_query(ec, &value);
- spin_lock_irqsave(&ec->lock, flags);
- acpi_hw_low_level_read(8, &value, &ec->command_addr);
- spin_unlock_irqrestore(&ec->lock, flags);
-
- /* TBD: Implement asynch events!
- * NOTE: All we care about are EC-SCI's. Other EC events are
- * handled via polling (yuck!). This is because some systems
- * treat EC-SCIs as level (versus EDGE!) triggered, preventing
- * a purely interrupt-driven approach (grumble, grumble).
- */
- if (!(value & ACPI_EC_FLAG_SCI))
+ if (result)
goto end;
- if (acpi_ec_query(ec, &value))
- goto end;
-
object_name[2] = hex[((value >> 4) & 0x0F)];
object_name[3] = hex[(value & 0x0F)];
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Evaluating %s\n", object_name));
acpi_evaluate_object(ec->handle, object_name, NULL, NULL);
-
-end:
- acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
+ atomic_dec(&ec->pending_gpe);
+end:
+ return;
}
static u32
@@ -390,6 +524,7 @@ acpi_ec_gpe_handler (
void *data)
{
acpi_status status = AE_OK;
+ u32 value;
struct acpi_ec *ec = (struct acpi_ec *) data;
if (!ec)
@@ -397,13 +532,39 @@ acpi_ec_gpe_handler (
acpi_disable_gpe(NULL, ec->gpe_bit, ACPI_ISR);
- status = acpi_os_queue_for_execution(OSD_PRIORITY_GPE,
- acpi_ec_gpe_query, ec);
+ value = acpi_ec_read_status(ec);
- if (status == AE_OK)
- return ACPI_INTERRUPT_HANDLED;
- else
- return ACPI_INTERRUPT_NOT_HANDLED;
+ if((value & ACPI_EC_FLAG_IBF) &&
+ !(value & ACPI_EC_FLAG_BURST) &&
+ (atomic_read(&ec->leaving_burst) == 0)) {
+ /*
+ * the embedded controller disables
+ * burst mode for any reason other
+ * than the burst disable command
+ * to process critical event.
+ */
+ atomic_set(&ec->leaving_burst , 2); /* block current pending transaction
+ and retry */
+ wake_up(&ec->wait);
+ }else {
+ if ((ec->expect_event == ACPI_EC_EVENT_OBF &&
+ (value & ACPI_EC_FLAG_OBF)) ||
+ (ec->expect_event == ACPI_EC_EVENT_IBE &&
+ !(value & ACPI_EC_FLAG_IBF))) {
+ ec->expect_event = 0;
+ wake_up(&ec->wait);
+
+ }
+ }
+
+ if (value & ACPI_EC_FLAG_SCI){
+ atomic_add(1, &ec->pending_gpe) ;
+ status = acpi_os_queue_for_execution(OSD_PRIORITY_GPE,
+ acpi_ec_gpe_query, ec);
+ }
+
+ return status == AE_OK ?
+ ACPI_INTERRUPT_HANDLED : ACPI_INTERRUPT_NOT_HANDLED;
}
/* --------------------------------------------------------------------------
@@ -421,10 +582,8 @@ acpi_ec_space_setup (
* The EC object is in the handler context and is needed
* when calling the acpi_ec_space_handler.
*/
- if(function == ACPI_REGION_DEACTIVATE)
- *return_context = NULL;
- else
- *return_context = handler_context;
+ *return_context = (function != ACPI_REGION_DEACTIVATE) ?
+ handler_context : NULL;
return AE_OK;
}
@@ -555,7 +714,7 @@ static int
acpi_ec_add_fs (
struct acpi_device *device)
{
- struct proc_dir_entry *entry = NULL;
+ struct proc_dir_entry *entry;
ACPI_FUNCTION_TRACE("acpi_ec_add_fs");
@@ -606,9 +765,9 @@ static int
acpi_ec_add (
struct acpi_device *device)
{
- int result = 0;
- acpi_status status = AE_OK;
- struct acpi_ec *ec = NULL;
+ int result;
+ acpi_status status;
+ struct acpi_ec *ec;
unsigned long uid;
ACPI_FUNCTION_TRACE("acpi_ec_add");
@@ -623,7 +782,10 @@ acpi_ec_add (
ec->handle = device->handle;
ec->uid = -1;
- spin_lock_init(&ec->lock);
+ atomic_set(&ec->pending_gpe, 0);
+ atomic_set(&ec->leaving_burst , 1);
+ init_MUTEX(&ec->sem);
+ init_waitqueue_head(&ec->wait);
strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
strcpy(acpi_device_class(device), ACPI_EC_CLASS);
acpi_driver_data(device) = ec;
@@ -637,7 +799,7 @@ acpi_ec_add (
if (ec_ecdt && ec_ecdt->uid == uid) {
acpi_remove_address_space_handler(ACPI_ROOT_OBJECT,
ACPI_ADR_SPACE_EC, &acpi_ec_space_handler);
-
+
acpi_remove_gpe_handler(NULL, ec_ecdt->gpe_bit, &acpi_ec_gpe_handler);
kfree(ec_ecdt);
@@ -677,7 +839,7 @@ acpi_ec_remove (
struct acpi_device *device,
int type)
{
- struct acpi_ec *ec = NULL;
+ struct acpi_ec *ec;
ACPI_FUNCTION_TRACE("acpi_ec_remove");
@@ -732,8 +894,8 @@ static int
acpi_ec_start (
struct acpi_device *device)
{
- acpi_status status = AE_OK;
- struct acpi_ec *ec = NULL;
+ acpi_status status;
+ struct acpi_ec *ec;
ACPI_FUNCTION_TRACE("acpi_ec_start");
@@ -789,8 +951,8 @@ acpi_ec_stop (
struct acpi_device *device,
int type)
{
- acpi_status status = AE_OK;
- struct acpi_ec *ec = NULL;
+ acpi_status status;
+ struct acpi_ec *ec;
ACPI_FUNCTION_TRACE("acpi_ec_stop");
@@ -832,7 +994,6 @@ acpi_fake_ecdt_callback (
status = acpi_evaluate_integer(handle, "_GPE", NULL, &ec_ecdt->gpe_bit);
if (ACPI_FAILURE(status))
return status;
- spin_lock_init(&ec_ecdt->lock);
ec_ecdt->global_lock = TRUE;
ec_ecdt->handle = handle;
@@ -890,7 +1051,7 @@ acpi_ec_get_real_ecdt(void)
acpi_status status;
struct acpi_table_ecdt *ecdt_ptr;
- status = acpi_get_firmware_table("ECDT", 1, ACPI_LOGICAL_ADDRESSING,
+ status = acpi_get_firmware_table("ECDT", 1, ACPI_LOGICAL_ADDRESSING,
(struct acpi_table_header **) &ecdt_ptr);
if (ACPI_FAILURE(status))
return -ENODEV;
@@ -905,11 +1066,12 @@ acpi_ec_get_real_ecdt(void)
return -ENOMEM;
memset(ec_ecdt, 0, sizeof(struct acpi_ec));
+ init_MUTEX(&ec_ecdt->sem);
+ init_waitqueue_head(&ec_ecdt->wait);
ec_ecdt->command_addr = ecdt_ptr->ec_control;
ec_ecdt->status_addr = ecdt_ptr->ec_control;
ec_ecdt->data_addr = ecdt_ptr->ec_data;
ec_ecdt->gpe_bit = ecdt_ptr->gpe_bit;
- spin_lock_init(&ec_ecdt->lock);
/* use the GL just to be safe */
ec_ecdt->global_lock = TRUE;
ec_ecdt->uid = ecdt_ptr->uid;
@@ -978,7 +1140,7 @@ error:
static int __init acpi_ec_init (void)
{
- int result = 0;
+ int result;
ACPI_FUNCTION_TRACE("acpi_ec_init");