ACPI / EC / PM: Fix race between EC transactions and suspend/hibernate process

PATCH Applied Rafael J. Wysocki 2 participants 9 messages Apr 8, 2010 – May 29, 2010 ACPI

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Rafael J. Wysocki

author

2010-04-08 23:38 UTC #0 lore raw

cover ACPI / EC / PM: Fix race between EC transactions and suspend/hibernate process

Hi Len,

The following two patches fix BKO #14668. The first one is the actual fix and the other one changes the names of the involved functions so that they better reflect what's done.

Please apply.

Rafael

Rafael J. Wysocki

author

2010-04-08 23:39 UTC #1 lore raw

PATCH 1/2 ACPI / EC / PM: Fix race between EC transactions and system suspend

There still is a race that may result in suspending the system in the middle of an EC transaction in progress, which leads to problems (like the kernel thinking that the ACPI global lock is held during resume while in fact it's not).

To remove the race condition, modify the ACPI platform suspend and hibernate callbacks so that EC transactions are blocked right after executing the _PTS global control method and are allowed to happen again right after the low-level wakeup.

Introduce acpi_pm_freeze() that will disable GPEs, wait until the event queues are empty and block EC transactions. Use it wherever GPEs are disabled in preparation for switching local interrupts off. Introduce acpi_pm_thaw() that will allow EC transactions to happen again and enable runtime GPEs. Use it to balance acpi_pm_freeze() wherever necessary.

In addition to that use acpi_ec_resume_transactions_early() to unblock EC transactions as early as reasonably possible during resume. Also unblock EC transactions in acpi_hibernation_finish() and in the analogous suspend routine to make sure that the EC transactions are enabled in all error paths.

Fixes https://bugzilla.kernel.org/show_bug.cgi?id=14668

Signed-off-by Rafael J. Wysocki <[email protected]>

Reported-and-tested-by Maxim Levitsky <[email protected]>

---
 drivers/acpi/ec.c       |   10 ++++++++
 drivers/acpi/internal.h |    1 
 drivers/acpi/sleep.c    |   55 +++++++++++++++++++++++++-----------------------
 3 files changed, 40 insertions(+), 26 deletions(-)

drivers/acpi/ec.c +10 -0

Index: linux-2.6/drivers/acpi/ec.c
===================================================================
@@ -485,6 +485,16 @@ void acpi_ec_resume_transactions(void)
 	mutex_unlock(&ec->lock);
 }
 
+void acpi_ec_resume_transactions_early(void)
+{
+	/*
+	 * Allow transactions to happen again (this function is called from
+	 * atomic context during wakeup, so we don't need to acquire the mutex).
+	 */
+	if (first_ec)
+		clear_bit(EC_FLAGS_FROZEN, &first_ec->flags);
+}
+
 static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 * data)
 {
 	int result;

drivers/acpi/internal.h +1 -0

Index: linux-2.6/drivers/acpi/internal.h
===================================================================
@@ -51,6 +51,7 @@ int acpi_ec_ecdt_probe(void);
 int acpi_boot_ec_enable(void);
 void acpi_ec_suspend_transactions(void);
 void acpi_ec_resume_transactions(void);
+void acpi_ec_resume_transactions_early(void);
 
 /*--------------------------------------------------------------------------
                                   Suspend/Resume

drivers/acpi/sleep.c +29 ~~-26~~

129 lines not on this page · raw message

Len Brown

reviewer Applied

2010-05-29 03:36 UTC #2 lore raw

Re: [PATCH 1/2] ACPI / EC / PM: Fix race between EC transactions and system suspend

applied

thanks,
Len Brown, Intel Open Source Technology Center

Len Brown

reviewer Applied

2010-05-29 03:36 UTC #3 lore raw

Re: [PATCH 1/2] ACPI / EC / PM: Fix race between EC transactions and system suspend

In reply to Rafael J. Wysocki

applied

thanks,
Len Brown, Intel Open Source Technology Center

Rafael J. Wysocki

author

2010-04-08 23:39 UTC #4 lore raw

PATCH 1/2 ACPI / EC / PM: Fix race between EC transactions and system suspend

In reply to Rafael J. Wysocki

Fixes https://bugzilla.kernel.org/show_bug.cgi?id=14668

Signed-off-by Rafael J. Wysocki <[email protected]>

Reported-and-tested-by Maxim Levitsky <[email protected]>

---
 drivers/acpi/ec.c       |   10 ++++++++
 drivers/acpi/internal.h |    1 
 drivers/acpi/sleep.c    |   55 +++++++++++++++++++++++++-----------------------
 3 files changed, 40 insertions(+), 26 deletions(-)

drivers/acpi/ec.c +10 -0

Index: linux-2.6/drivers/acpi/ec.c
===================================================================
@@ -485,6 +485,16 @@ void acpi_ec_resume_transactions(void)
 	mutex_unlock(&ec->lock);
 }
 
+void acpi_ec_resume_transactions_early(void)
+{
+	/*
+	 * Allow transactions to happen again (this function is called from
+	 * atomic context during wakeup, so we don't need to acquire the mutex).
+	 */
+	if (first_ec)
+		clear_bit(EC_FLAGS_FROZEN, &first_ec->flags);
+}
+
 static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 * data)
 {
 	int result;

drivers/acpi/internal.h +1 -0

Index: linux-2.6/drivers/acpi/internal.h
===================================================================
@@ -51,6 +51,7 @@ int acpi_ec_ecdt_probe(void);
 int acpi_boot_ec_enable(void);
 void acpi_ec_suspend_transactions(void);
 void acpi_ec_resume_transactions(void);
+void acpi_ec_resume_transactions_early(void);
 
 /*--------------------------------------------------------------------------
                                   Suspend/Resume

drivers/acpi/sleep.c +29 ~~-26~~

129 lines not on this page · raw message

Rafael J. Wysocki

author

2010-04-08 23:38 UTC #5 lore raw

PATCH 2/2 ACPI / EC / PM: Fix names of functions that block/unblock EC transactions

In reply to Rafael J. Wysocki

The names of the functions used for blocking/unblocking EC transactions during suspend/hibernation suggest that the transactions are suspended and resumed by them, while in fact they are disabled and enabled. Rename the functions (and the flag used by them) to better reflect what they really do.

Signed-off-by Rafael J. Wysocki <[email protected]>

---
 drivers/acpi/ec.c       |   16 ++++++++--------
 drivers/acpi/internal.h |    6 +++---
 drivers/acpi/sleep.c    |   12 ++++++------
 3 files changed, 17 insertions(+), 17 deletions(-)

drivers/acpi/ec.c +8 -8

Index: linux-2.6/drivers/acpi/ec.c
===================================================================
@@ -79,7 +79,7 @@ enum {
 	EC_FLAGS_GPE_STORM,		/* GPE storm detected */
 	EC_FLAGS_HANDLERS_INSTALLED,	/* Handlers for GPE and
 					 * OpReg are installed */
-	EC_FLAGS_FROZEN,		/* Transactions are suspended */
+	EC_FLAGS_BLOCKED,		/* Transactions are blocked */
 };
 
 /* If we find an EC via the ECDT, we need to keep a ptr to its context */

@@ -293,7 +293,7 @@ static int acpi_ec_transaction(struct ac
 	if (t->rdata)
 		memset(t->rdata, 0, t->rlen);
 	mutex_lock(&ec->lock);
-	if (test_bit(EC_FLAGS_FROZEN, &ec->flags)) {
+	if (test_bit(EC_FLAGS_BLOCKED, &ec->flags)) {
 		status = -EINVAL;
 		goto unlock;
 	}

@@ -459,7 +459,7 @@ int ec_transaction(u8 command,
 
 EXPORT_SYMBOL(ec_transaction);
 
-void acpi_ec_suspend_transactions(void)
+void acpi_ec_block_transactions(void)
 {
 	struct acpi_ec *ec = first_ec;

@@ -468,11 +468,11 @@ void acpi_ec_suspend_transactions(void)
 
 	mutex_lock(&ec->lock);
 	/* Prevent transactions from being carried out */
-	set_bit(EC_FLAGS_FROZEN, &ec->flags);
+	set_bit(EC_FLAGS_BLOCKED, &ec->flags);
 	mutex_unlock(&ec->lock);
 }
 
-void acpi_ec_resume_transactions(void)
+void acpi_ec_unblock_transactions(void)
 {
 	struct acpi_ec *ec = first_ec;

@@ -481,18 +481,18 @@ void acpi_ec_resume_transactions(void)
 
 	mutex_lock(&ec->lock);
 	/* Allow transactions to be carried out again */
-	clear_bit(EC_FLAGS_FROZEN, &ec->flags);
+	clear_bit(EC_FLAGS_BLOCKED, &ec->flags);
 	mutex_unlock(&ec->lock);
 }
 
-void acpi_ec_resume_transactions_early(void)
+void acpi_ec_unblock_transactions_early(void)
 {
 	/*
 	 * Allow transactions to happen again (this function is called from
 	 * atomic context during wakeup, so we don't need to acquire the mutex).
 	 */
 	if (first_ec)
-		clear_bit(EC_FLAGS_FROZEN, &first_ec->flags);
+		clear_bit(EC_FLAGS_BLOCKED, &first_ec->flags);
 }
 
 static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 * data)

drivers/acpi/internal.h +3 -3

Index: linux-2.6/drivers/acpi/internal.h
===================================================================
@@ -49,9 +49,9 @@ void acpi_early_processor_set_pdc(void);
 int acpi_ec_init(void);
 int acpi_ec_ecdt_probe(void);
 int acpi_boot_ec_enable(void);
-void acpi_ec_suspend_transactions(void);
-void acpi_ec_resume_transactions(void);
-void acpi_ec_resume_transactions_early(void);
+void acpi_ec_block_transactions(void);
+void acpi_ec_unblock_transactions(void);
+void acpi_ec_unblock_transactions_early(void);
 
 /*--------------------------------------------------------------------------
                                   Suspend/Resume

drivers/acpi/sleep.c +6 -6

Index: linux-2.6/drivers/acpi/sleep.c
===================================================================
@@ -116,7 +116,7 @@ static int acpi_pm_freeze(void)
 {
 	acpi_disable_all_gpes();
 	acpi_os_wait_events_complete(NULL);
-	acpi_ec_suspend_transactions();
+	acpi_ec_block_transactions();
 	return 0;
 }

@@ -279,7 +279,7 @@ static int acpi_suspend_enter(suspend_st
 	 */
 	acpi_disable_all_gpes();
 	/* Allow EC transactions to happen. */
-	acpi_ec_resume_transactions_early();
+	acpi_ec_unblock_transactions_early();
 
 	local_irq_restore(flags);
 	printk(KERN_DEBUG "Back to C!\n");

@@ -293,7 +293,7 @@ static int acpi_suspend_enter(suspend_st
 
 static void acpi_suspend_finish(void)
 {
-	acpi_ec_resume_transactions();
+	acpi_ec_unblock_transactions();
 	acpi_pm_finish();
 }

@@ -541,7 +541,7 @@ static int acpi_hibernation_enter(void)
 static void acpi_hibernation_finish(void)
 {
 	hibernate_nvs_free();
-	acpi_ec_resume_transactions();
+	acpi_ec_unblock_transactions();
 	acpi_pm_finish();
 }

@@ -563,12 +563,12 @@ static void acpi_hibernation_leave(void)
 	/* Restore the NVS memory area */
 	hibernate_nvs_restore();
 	/* Allow EC transactions to happen. */
-	acpi_ec_resume_transactions_early();
+	acpi_ec_unblock_transactions_early();
 }
 
 static void acpi_pm_thaw(void)
 {
-	acpi_ec_resume_transactions();
+	acpi_ec_unblock_transactions();
 	acpi_enable_all_runtime_gpes();
 }

Len Brown

reviewer Applied

2010-05-29 03:36 UTC #6 lore raw

Re: [PATCH 2/2] ACPI / EC / PM: Fix names of functions that block/unblock EC transactions

applied

thanks,
Len Brown, Intel Open Source Technology Center

Len Brown

reviewer Applied

2010-05-29 03:36 UTC #7 lore raw

Re: [PATCH 2/2] ACPI / EC / PM: Fix names of functions that block/unblock EC transactions

In reply to Rafael J. Wysocki

applied

thanks,
Len Brown, Intel Open Source Technology Center

Rafael J. Wysocki

author

2010-04-08 23:40 UTC #8 lore raw

PATCH 2/2 ACPI / EC / PM: Fix names of functions that block/unblock EC transactions

In reply to Rafael J. Wysocki

Signed-off-by Rafael J. Wysocki <[email protected]>

---
 drivers/acpi/ec.c       |   16 ++++++++--------
 drivers/acpi/internal.h |    6 +++---
 drivers/acpi/sleep.c    |   12 ++++++------
 3 files changed, 17 insertions(+), 17 deletions(-)

drivers/acpi/ec.c +8 -8

Index: linux-2.6/drivers/acpi/ec.c
===================================================================
@@ -79,7 +79,7 @@ enum {
 	EC_FLAGS_GPE_STORM,		/* GPE storm detected */
 	EC_FLAGS_HANDLERS_INSTALLED,	/* Handlers for GPE and
 					 * OpReg are installed */
-	EC_FLAGS_FROZEN,		/* Transactions are suspended */
+	EC_FLAGS_BLOCKED,		/* Transactions are blocked */
 };
 
 /* If we find an EC via the ECDT, we need to keep a ptr to its context */

@@ -293,7 +293,7 @@ static int acpi_ec_transaction(struct ac
 	if (t->rdata)
 		memset(t->rdata, 0, t->rlen);
 	mutex_lock(&ec->lock);
-	if (test_bit(EC_FLAGS_FROZEN, &ec->flags)) {
+	if (test_bit(EC_FLAGS_BLOCKED, &ec->flags)) {
 		status = -EINVAL;
 		goto unlock;
 	}

@@ -459,7 +459,7 @@ int ec_transaction(u8 command,
 
 EXPORT_SYMBOL(ec_transaction);
 
-void acpi_ec_suspend_transactions(void)
+void acpi_ec_block_transactions(void)
 {
 	struct acpi_ec *ec = first_ec;

@@ -468,11 +468,11 @@ void acpi_ec_suspend_transactions(void)
 
 	mutex_lock(&ec->lock);
 	/* Prevent transactions from being carried out */
-	set_bit(EC_FLAGS_FROZEN, &ec->flags);
+	set_bit(EC_FLAGS_BLOCKED, &ec->flags);
 	mutex_unlock(&ec->lock);
 }
 
-void acpi_ec_resume_transactions(void)
+void acpi_ec_unblock_transactions(void)
 {
 	struct acpi_ec *ec = first_ec;

@@ -481,18 +481,18 @@ void acpi_ec_resume_transactions(void)
 
 	mutex_lock(&ec->lock);
 	/* Allow transactions to be carried out again */
-	clear_bit(EC_FLAGS_FROZEN, &ec->flags);
+	clear_bit(EC_FLAGS_BLOCKED, &ec->flags);
 	mutex_unlock(&ec->lock);
 }
 
-void acpi_ec_resume_transactions_early(void)
+void acpi_ec_unblock_transactions_early(void)
 {
 	/*
 	 * Allow transactions to happen again (this function is called from
 	 * atomic context during wakeup, so we don't need to acquire the mutex).
 	 */
 	if (first_ec)
-		clear_bit(EC_FLAGS_FROZEN, &first_ec->flags);
+		clear_bit(EC_FLAGS_BLOCKED, &first_ec->flags);
 }
 
 static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 * data)

drivers/acpi/internal.h +3 -3

Index: linux-2.6/drivers/acpi/internal.h
===================================================================
@@ -49,9 +49,9 @@ void acpi_early_processor_set_pdc(void);
 int acpi_ec_init(void);
 int acpi_ec_ecdt_probe(void);
 int acpi_boot_ec_enable(void);
-void acpi_ec_suspend_transactions(void);
-void acpi_ec_resume_transactions(void);
-void acpi_ec_resume_transactions_early(void);
+void acpi_ec_block_transactions(void);
+void acpi_ec_unblock_transactions(void);
+void acpi_ec_unblock_transactions_early(void);
 
 /*--------------------------------------------------------------------------
                                   Suspend/Resume

drivers/acpi/sleep.c +6 -6

Index: linux-2.6/drivers/acpi/sleep.c
===================================================================
@@ -116,7 +116,7 @@ static int acpi_pm_freeze(void)
 {
 	acpi_disable_all_gpes();
 	acpi_os_wait_events_complete(NULL);
-	acpi_ec_suspend_transactions();
+	acpi_ec_block_transactions();
 	return 0;
 }

@@ -279,7 +279,7 @@ static int acpi_suspend_enter(suspend_st
 	 */
 	acpi_disable_all_gpes();
 	/* Allow EC transactions to happen. */
-	acpi_ec_resume_transactions_early();
+	acpi_ec_unblock_transactions_early();
 
 	local_irq_restore(flags);
 	printk(KERN_DEBUG "Back to C!\n");

@@ -293,7 +293,7 @@ static int acpi_suspend_enter(suspend_st
 
 static void acpi_suspend_finish(void)
 {
-	acpi_ec_resume_transactions();
+	acpi_ec_unblock_transactions();
 	acpi_pm_finish();
 }

@@ -541,7 +541,7 @@ static int acpi_hibernation_enter(void)
 static void acpi_hibernation_finish(void)
 {
 	hibernate_nvs_free();
-	acpi_ec_resume_transactions();
+	acpi_ec_unblock_transactions();
 	acpi_pm_finish();
 }

@@ -563,12 +563,12 @@ static void acpi_hibernation_leave(void)
 	/* Restore the NVS memory area */
 	hibernate_nvs_restore();
 	/* Allow EC transactions to happen. */
-	acpi_ec_resume_transactions_early();
+	acpi_ec_unblock_transactions_early();
 }
 
 static void acpi_pm_thaw(void)
 {
-	acpi_ec_resume_transactions();
+	acpi_ec_unblock_transactions();
 	acpi_enable_all_runtime_gpes();
 }