Here is the same patch as attachment for your convenience.
Alexey Starikovskiy wrote:
Hi Andy,
I just uploaded patch for bugs 9998 and 10724, which solves the problem
of interrupt storm more cleanly.
Could you please add this patch to testing?
Thanks,
Alex.
ACPI: EC: do transaction from interrupt context
From: Alexey Starikovskiy <astarikovskiy@xxxxxxx>
It is easier and faster to do transaction directly from interrupt context
rather than waking control thread.
Also, cleaner GPE storm avoidance is implemented.
Signed-off-by: Alexey Starikovskiy <astarikovskiy@xxxxxxx>
---
drivers/acpi/ec.c | 250 ++++++++++++++++++++++++-----------------------------
1 files changed, 113 insertions(+), 137 deletions(-)
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 13593f9..1f96f0e 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -1,7 +1,7 @@
/*
- * ec.c - ACPI Embedded Controller Driver (v2.0)
+ * ec.c - ACPI Embedded Controller Driver (v2.1)
*
- * Copyright (C) 2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@xxxxxxxxx>
+ * Copyright (C) 2006-2008 Alexey Starikovskiy <astarikovskiy@xxxxxxx>
* Copyright (C) 2006 Denis Sadykov <denis.m.sadykov@xxxxxxxxx>
* Copyright (C) 2004 Luming Yu <luming.yu@xxxxxxxxx>
* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@xxxxxxxxx>
@@ -26,7 +26,7 @@
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
-/* Uncomment next line to get verbose print outs*/
+/* Uncomment next line to get verbose printout */
/* #define DEBUG */
#include <linux/kernel.h>
@@ -65,22 +65,18 @@ enum ec_command {
ACPI_EC_COMMAND_QUERY = 0x84,
};
-/* EC events */
-enum ec_event {
- ACPI_EC_EVENT_OBF_1 = 1, /* Output buffer full */
- ACPI_EC_EVENT_IBF_0, /* Input buffer empty */
-};
-
#define ACPI_EC_DELAY 500 /* Wait 500ms max. during EC ops */
#define ACPI_EC_UDELAY_GLK 1000 /* Wait 1ms max. to get global lock */
#define ACPI_EC_UDELAY 100 /* Wait 100us before polling EC again */
+#define ACPI_EC_STORM_THRESHOLD 20 /* number of false interrupts
+ per one transaction */
+
enum {
- EC_FLAGS_WAIT_GPE = 0, /* Don't check status until GPE arrives */
EC_FLAGS_QUERY_PENDING, /* Query is pending */
EC_FLAGS_GPE_MODE, /* Expect GPE to be sent for status change */
EC_FLAGS_NO_GPE, /* Don't use GPE mode */
- EC_FLAGS_RESCHEDULE_POLL /* Re-schedule poll */
+ EC_FLAGS_GPE_STORM /* GPE storm detected */
};
/* If we find an EC via the ECDT, we need to keep a ptr to its context */
@@ -95,6 +91,14 @@ struct acpi_ec_query_handler {
u8 query_bit;
};
+struct transaction_data {
+ const u8 *wdata;
+ u8 *rdata;
+ u8 command;
+ u8 wlen;
+ u8 rlen;
+};
+
static struct acpi_ec {
acpi_handle handle;
unsigned long gpe;
@@ -105,7 +109,7 @@ static struct acpi_ec {
struct mutex lock;
wait_queue_head_t wait;
struct list_head list;
- struct delayed_work work;
+ struct transaction_data t;
atomic_t irq_count;
u8 handlers_installed;
} *boot_ec, *first_ec;
@@ -150,13 +154,13 @@ static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
{
u8 x = inb(ec->data_addr);
pr_debug(PREFIX "---> data = 0x%2.2x\n", x);
- return inb(ec->data_addr);
+ return x;
}
static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
{
pr_debug(PREFIX "<--- command = 0x%2.2x\n", command);
- outb(command, ec->command_addr);
+ outb((ec->t.command = command), ec->command_addr);
}
static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
@@ -165,69 +169,60 @@ static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
outb(data, ec->data_addr);
}
-static inline int acpi_ec_check_status(struct acpi_ec *ec, enum ec_event event)
-{
- if (test_bit(EC_FLAGS_WAIT_GPE, &ec->flags))
- return 0;
- if (event == ACPI_EC_EVENT_OBF_1) {
- if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_OBF)
- return 1;
- } else if (event == ACPI_EC_EVENT_IBF_0) {
- if (!(acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF))
- return 1;
- }
-
+static int ec_transaction_done(struct acpi_ec *ec) {
+ if (!ec->t.command)
+ return 1;
+ if (!ec->t.wlen && !ec->t.rlen)
+ return 1;
return 0;
}
-static void ec_schedule_ec_poll(struct acpi_ec *ec)
+static void gpe_transaction(struct acpi_ec *ec, u8 status)
{
- if (test_bit(EC_FLAGS_RESCHEDULE_POLL, &ec->flags))
- schedule_delayed_work(&ec->work,
- msecs_to_jiffies(ACPI_EC_DELAY));
+ if (!ec->t.command)
+ return;
+ if (ec->t.wlen > 0) {
+ if ((status & ACPI_EC_FLAG_IBF) == 0) {
+ acpi_ec_write_data(ec, *(ec->t.wdata++));
+ --ec->t.wlen;
+ } else
+ /* false interrupt, state didn't change */
+ atomic_inc(&ec->irq_count);
+
+ } else if (ec->t.rlen > 0) {
+ if ((status & ACPI_EC_FLAG_OBF) == 1) {
+ *(ec->t.rdata++) = acpi_ec_read_data(ec);
+ --ec->t.rlen;
+ } else
+ /* false interrupt, state didn't change */
+ atomic_inc(&ec->irq_count);
+ }
}
-static void ec_switch_to_poll_mode(struct acpi_ec *ec)
+static int acpi_ec_wait(struct acpi_ec *ec)
{
+ if (wait_event_timeout(ec->wait, ec_transaction_done(ec),
+ msecs_to_jiffies(ACPI_EC_DELAY)))
+ return 0;
+ /* missing GPEs, switch back to poll mode */
+ if (printk_ratelimit())
+ pr_info(PREFIX "missing confirmations, "
+ "switch off interrupt mode.\n");
set_bit(EC_FLAGS_NO_GPE, &ec->flags);
clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);
- acpi_disable_gpe(NULL, ec->gpe, ACPI_NOT_ISR);
- set_bit(EC_FLAGS_RESCHEDULE_POLL, &ec->flags);
+ return 1;
}
-static int acpi_ec_wait(struct acpi_ec *ec, enum ec_event event, int force_poll)
+static void acpi_ec_gpe_query(void *ec_cxt);
+
+static int ec_check_sci(struct acpi_ec *ec, u8 state)
{
- atomic_set(&ec->irq_count, 0);
- if (likely(test_bit(EC_FLAGS_GPE_MODE, &ec->flags)) &&
- likely(!force_poll)) {
- if (wait_event_timeout(ec->wait, acpi_ec_check_status(ec, event),
- msecs_to_jiffies(ACPI_EC_DELAY)))
- return 0;
- clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
- if (acpi_ec_check_status(ec, event)) {
- /* missing GPEs, switch back to poll mode */
- if (printk_ratelimit())
- pr_info(PREFIX "missing confirmations, "
- "switch off interrupt mode.\n");
- ec_switch_to_poll_mode(ec);
- ec_schedule_ec_poll(ec);
- return 0;
- }
- } else {
- unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);
- clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
- while (time_before(jiffies, delay)) {
- if (acpi_ec_check_status(ec, event))
- return 0;
- msleep(1);
- }
- if (acpi_ec_check_status(ec,event))
- return 0;
+ if (state & ACPI_EC_FLAG_SCI) {
+ if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
+ return acpi_os_execute(OSL_EC_BURST_HANDLER,
+ acpi_ec_gpe_query, ec);
}
- pr_err(PREFIX "acpi_ec_wait timeout, status = 0x%2.2x, event = %s\n",
- acpi_ec_read_status(ec),
- (event == ACPI_EC_EVENT_OBF_1) ? "\"b0=1\"" : "\"b1=0\"");
- return -ETIME;
+ return 0;
}
static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, u8 command,
@@ -235,45 +230,53 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, u8 command,
u8 * rdata, unsigned rdata_len,
int force_poll)
{
- int result = 0;
- set_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
+ unsigned long delay;
pr_debug(PREFIX "transaction start\n");
- acpi_ec_write_cmd(ec, command);
- for (; wdata_len > 0; --wdata_len) {
- result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, force_poll);
- if (result) {
- pr_err(PREFIX
- "write_cmd timeout, command = %d\n", command);
- goto end;
- }
- set_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
- acpi_ec_write_data(ec, *(wdata++));
+ /* disable GPE during transaction if storm is detected */
+ if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
+ set_bit(EC_FLAGS_NO_GPE, &ec->flags);
+ clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);
+ acpi_disable_gpe(NULL, ec->gpe, ACPI_NOT_ISR);
}
-
- if (!rdata_len) {
- result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, force_poll);
- if (result) {
- pr_err(PREFIX
- "finish-write timeout, command = %d\n", command);
- goto end;
- }
- } else if (command == ACPI_EC_COMMAND_QUERY)
- clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
-
- for (; rdata_len > 0; --rdata_len) {
- result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF_1, force_poll);
- if (result) {
- pr_err(PREFIX "read timeout, command = %d\n", command);
- goto end;
+ atomic_set(&ec->irq_count, 0);
+ /* fill in transaction structure */
+ ec->t.wdata = wdata;
+ ec->t.wlen = wdata_len;
+ ec->t.rdata = rdata;
+ ec->t.rlen = rdata_len;
+ /* start transaction */
+ acpi_ec_write_cmd(ec, command);
+ /* if we selected poll mode or failed in GPE-mode do a poll loop */
+ if (force_poll ||
+ !test_bit(EC_FLAGS_GPE_MODE, &ec->flags) ||
+ acpi_ec_wait(ec)) {
+ delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);
+ while (time_before(jiffies, delay)) {
+ gpe_transaction(ec, acpi_ec_read_status(ec));
+ msleep(1);
+ if (ec_transaction_done(ec))
+ goto end;
}
- /* Don't expect GPE after last read */
- if (rdata_len > 1)
- set_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
- *(rdata++) = acpi_ec_read_data(ec);
}
- end:
+end:
pr_debug(PREFIX "transaction end\n");
- return result;
+ ec->t.command = 0;
+ if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
+ /* check if we received SCI during transaction */
+ ec_check_sci(ec, acpi_ec_read_status(ec));
+ /* it is safe to enable GPE outside of transaction */
+ acpi_enable_gpe(NULL, ec->gpe, ACPI_NOT_ISR);
+ } else if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags) &&
+ atomic_read(&ec->irq_count) > ACPI_EC_STORM_THRESHOLD)
+ pr_debug(PREFIX "GPE storm detected\n");
+ set_bit(EC_FLAGS_GPE_STORM, &ec->flags);
+ return 0;
+}
+
+static int ec_check_ibf0(struct acpi_ec *ec)
+{
+ u8 status = acpi_ec_read_status(ec);
+ return (status & ACPI_EC_FLAG_IBF) == 0;
}
static int acpi_ec_transaction(struct acpi_ec *ec, u8 command,
@@ -299,8 +302,8 @@ static int acpi_ec_transaction(struct acpi_ec *ec, u8 command,
}
}
- status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, 0);
- if (status) {
+ if (!wait_event_timeout(ec->wait, ec_check_ibf0(ec),
+ msecs_to_jiffies(ACPI_EC_DELAY))) {
pr_err(PREFIX "input buffer is not empty, "
"aborting transaction\n");
goto end;
@@ -437,6 +440,7 @@ static int acpi_ec_query(struct acpi_ec *ec, u8 * data)
*/
result = acpi_ec_transaction(ec, ACPI_EC_COMMAND_QUERY, NULL, 0, &d, 1, 0);
+ clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
if (result)
return result;
@@ -515,24 +519,17 @@ static u32 acpi_ec_gpe_handler(void *data)
{
acpi_status status = AE_OK;
struct acpi_ec *ec = data;
- u8 state = acpi_ec_read_status(ec);
+ u8 state;
pr_debug(PREFIX "~~~> interrupt\n");
- atomic_inc(&ec->irq_count);
- if (atomic_read(&ec->irq_count) > 5) {
- pr_err(PREFIX "GPE storm detected, disabling EC GPE\n");
- ec_switch_to_poll_mode(ec);
- goto end;
- }
- clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
- if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags))
+ state = acpi_ec_read_status(ec);
+
+ gpe_transaction(ec, state);
+ if ((status & ACPI_EC_FLAG_IBF) == 0)
wake_up(&ec->wait);
- if (state & ACPI_EC_FLAG_SCI) {
- if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
- status = acpi_os_execute(OSL_EC_BURST_HANDLER,
- acpi_ec_gpe_query, ec);
- } else if (!test_bit(EC_FLAGS_GPE_MODE, &ec->flags) &&
+ status = ec_check_sci(ec, state);
+ if (!test_bit(EC_FLAGS_GPE_MODE, &ec->flags) &&
!test_bit(EC_FLAGS_NO_GPE, &ec->flags) &&
in_interrupt()) {
/* this is non-query, must be confirmation */
@@ -540,21 +537,11 @@ static u32 acpi_ec_gpe_handler(void *data)
pr_info(PREFIX "non-query interrupt received,"
" switching to interrupt mode\n");
set_bit(EC_FLAGS_GPE_MODE, &ec->flags);
- clear_bit(EC_FLAGS_RESCHEDULE_POLL, &ec->flags);
}
-end:
- ec_schedule_ec_poll(ec);
return ACPI_SUCCESS(status) ?
ACPI_INTERRUPT_HANDLED : ACPI_INTERRUPT_NOT_HANDLED;
}
-static void do_ec_poll(struct work_struct *work)
-{
- struct acpi_ec *ec = container_of(work, struct acpi_ec, work.work);
- atomic_set(&ec->irq_count, 0);
- (void)acpi_ec_gpe_handler(ec);
-}
-
/* --------------------------------------------------------------------------
Address Space Management
-------------------------------------------------------------------------- */
@@ -696,7 +683,6 @@ static struct acpi_ec *make_acpi_ec(void)
mutex_init(&ec->lock);
init_waitqueue_head(&ec->wait);
INIT_LIST_HEAD(&ec->list);
- INIT_DELAYED_WORK_DEFERRABLE(&ec->work, do_ec_poll);
atomic_set(&ec->irq_count, 0);
return ec;
}
@@ -736,15 +722,8 @@ ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
return AE_CTRL_TERMINATE;
}
-static void ec_poll_stop(struct acpi_ec *ec)
-{
- clear_bit(EC_FLAGS_RESCHEDULE_POLL, &ec->flags);
- cancel_delayed_work(&ec->work);
-}
-
static void ec_remove_handlers(struct acpi_ec *ec)
{
- ec_poll_stop(ec);
if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
pr_err(PREFIX "failed to remove space handler\n");
@@ -849,14 +828,12 @@ static int ec_install_handlers(struct acpi_ec *ec)
if (ec->handlers_installed)
return 0;
status = acpi_install_gpe_handler(NULL, ec->gpe,
- ACPI_GPE_EDGE_TRIGGERED,
- &acpi_ec_gpe_handler, ec);
+ ACPI_GPE_EDGE_TRIGGERED,
+ &acpi_ec_gpe_handler, ec);
if (ACPI_FAILURE(status))
return -ENODEV;
-
acpi_set_gpe_type(NULL, ec->gpe, ACPI_GPE_TYPE_RUNTIME);
acpi_enable_gpe(NULL, ec->gpe, ACPI_NOT_ISR);
-
status = acpi_install_address_space_handler(ec->handle,
ACPI_ADR_SPACE_EC,
&acpi_ec_space_handler,
@@ -887,7 +864,6 @@ static int acpi_ec_start(struct acpi_device *device)
/* EC is fully operational, allow queries */
clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
- ec_schedule_ec_poll(ec);
return ret;
}
