On Wednesday, March 23, 2011, Lin Ming wrote:
> Commit 9cd0314(ACPI / ACPICA: Fix global lock acquisition) was backported
> into ACPICA code base, and some divergence was introduced.
>
> This patch fixed it,
> - rename acpi_ev_global_lock_pending/acpi_ev_global_lock_pending_lock
> to acpi_gbl_global_lock_pending/acpi_gbl_global_lock_pending_lock.
>
> - move the initialization of acpi_gbl_global_lock_pending_lock from
> acpi_ut_mutex_initialize to acpi_ev_init_global_lock_handler.
>
> Signed-off-by: Lin Ming <ming.m.lin@xxxxxxxxx>
Reviewed-by: Rafael J. Wysocki <rjw@xxxxxxx>
> ---
> drivers/acpi/acpica/acglobal.h | 6 ++-
> drivers/acpi/acpica/evmisc.c | 74 +++++++++++++++++++++------------------
> drivers/acpi/acpica/utmutex.c | 5 ---
> 3 files changed, 44 insertions(+), 41 deletions(-)
>
> diff --git a/drivers/acpi/acpica/acglobal.h b/drivers/acpi/acpica/acglobal.h
> index 6d512fc..73863d8 100644
> --- a/drivers/acpi/acpica/acglobal.h
> +++ b/drivers/acpi/acpica/acglobal.h
> @@ -214,13 +214,16 @@ ACPI_EXTERN struct acpi_mutex_info acpi_gbl_mutex_info[ACPI_NUM_MUTEX];
>
> /*
> * Global lock mutex is an actual AML mutex object
> - * Global lock semaphore works in conjunction with the HW global lock
> + * Global lock semaphore works in conjunction with the actual global lock
> + * Global lock spinlock is used for "pending" handshake
> */
> ACPI_EXTERN union acpi_operand_object *acpi_gbl_global_lock_mutex;
> ACPI_EXTERN acpi_semaphore acpi_gbl_global_lock_semaphore;
> +ACPI_EXTERN acpi_spinlock acpi_gbl_global_lock_pending_lock;
> ACPI_EXTERN u16 acpi_gbl_global_lock_handle;
> ACPI_EXTERN u8 acpi_gbl_global_lock_acquired;
> ACPI_EXTERN u8 acpi_gbl_global_lock_present;
> +ACPI_EXTERN u8 acpi_gbl_global_lock_pending;
>
> /*
> * Spinlocks are used for interfaces that can be possibly called at
> @@ -228,7 +231,6 @@ ACPI_EXTERN u8 acpi_gbl_global_lock_present;
> */
> ACPI_EXTERN acpi_spinlock acpi_gbl_gpe_lock; /* For GPE data structs and registers */
> ACPI_EXTERN acpi_spinlock acpi_gbl_hardware_lock; /* For ACPI H/W except GPE registers */
> -ACPI_EXTERN acpi_spinlock acpi_ev_global_lock_pending_lock; /* For global lock */
>
> /*****************************************************************************
> *
> diff --git a/drivers/acpi/acpica/evmisc.c b/drivers/acpi/acpica/evmisc.c
> index 7dc8094..69a3b4a 100644
> --- a/drivers/acpi/acpica/evmisc.c
> +++ b/drivers/acpi/acpica/evmisc.c
> @@ -284,39 +284,41 @@ static void ACPI_SYSTEM_XFACE acpi_ev_notify_dispatch(void *context)
> * RETURN: ACPI_INTERRUPT_HANDLED
> *
> * DESCRIPTION: Invoked directly from the SCI handler when a global lock
> - * release interrupt occurs. If there's a thread waiting for
> - * the global lock, signal it.
> - *
> - * NOTE: Assumes that the semaphore can be signaled from interrupt level. If
> - * this is not possible for some reason, a separate thread will have to be
> - * scheduled to do this.
> + * release interrupt occurs. If there is actually a pending
> + * request for the lock, signal the waiting thread.
> *
> ******************************************************************************/
> -static u8 acpi_ev_global_lock_pending;
>
> static u32 acpi_ev_global_lock_handler(void *context)
> {
> acpi_status status;
> acpi_cpu_flags flags;
>
> - flags = acpi_os_acquire_lock(acpi_ev_global_lock_pending_lock);
> + flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock);
>
> - if (!acpi_ev_global_lock_pending) {
> - goto out;
> + /*
> + * If a request for the global lock is not actually pending,
> + * we are done. This handles "spurious" global lock interrupts
> + * which are possible (and have been seen) with bad BIOSs.
> + */
> + if (!acpi_gbl_global_lock_pending) {
> + goto cleanup_and_exit;
> }
>
> - /* Send a unit to the semaphore */
> -
> + /*
> + * Send a unit to the global lock semaphore. The actual acquisition
> + * of the global lock will be performed by the waiting thread.
> + */
> status = acpi_os_signal_semaphore(acpi_gbl_global_lock_semaphore, 1);
> if (ACPI_FAILURE(status)) {
> ACPI_ERROR((AE_INFO, "Could not signal Global Lock semaphore"));
> }
>
> - acpi_ev_global_lock_pending = FALSE;
> + acpi_gbl_global_lock_pending = FALSE;
>
> - out:
> - acpi_os_release_lock(acpi_ev_global_lock_pending_lock, flags);
> +cleanup_and_exit:
>
> + acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags);
> return (ACPI_INTERRUPT_HANDLED);
> }
>
> @@ -350,14 +352,20 @@ acpi_status acpi_ev_init_global_lock_handler(void)
> * Map to AE_OK, but mark global lock as not present. Any attempt to
> * actually use the global lock will be flagged with an error.
> */
> + acpi_gbl_global_lock_present = FALSE;
> if (status == AE_NO_HARDWARE_RESPONSE) {
> ACPI_ERROR((AE_INFO,
> "No response from Global Lock hardware, disabling lock"));
>
> - acpi_gbl_global_lock_present = FALSE;
> return_ACPI_STATUS(AE_OK);
> }
>
> + status = acpi_os_create_lock(&acpi_gbl_global_lock_pending_lock);
> + if (ACPI_FAILURE(status)) {
> + return_ACPI_STATUS(status);
> + }
> +
> + acpi_gbl_global_lock_pending = FALSE;
> acpi_gbl_global_lock_present = TRUE;
> return_ACPI_STATUS(status);
> }
> @@ -414,7 +422,7 @@ static int acpi_ev_global_lock_acquired;
> acpi_status acpi_ev_acquire_global_lock(u16 timeout)
> {
> acpi_cpu_flags flags;
> - acpi_status status = AE_OK;
> + acpi_status status;
> u8 acquired = FALSE;
>
> ACPI_FUNCTION_TRACE(ev_acquire_global_lock);
> @@ -458,15 +466,15 @@ acpi_status acpi_ev_acquire_global_lock(u16 timeout)
> }
>
> /*
> - * Make sure that a global lock actually exists. If not, just treat the
> - * lock as a standard mutex.
> + * Make sure that a global lock actually exists. If not, just
> + * treat the lock as a standard mutex.
> */
> if (!acpi_gbl_global_lock_present) {
> acpi_gbl_global_lock_acquired = TRUE;
> return_ACPI_STATUS(AE_OK);
> }
>
> - flags = acpi_os_acquire_lock(acpi_ev_global_lock_pending_lock);
> + flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock);
>
> do {
>
> @@ -475,20 +483,19 @@ acpi_status acpi_ev_acquire_global_lock(u16 timeout)
> ACPI_ACQUIRE_GLOBAL_LOCK(acpi_gbl_FACS, acquired);
> if (acquired) {
> acpi_gbl_global_lock_acquired = TRUE;
> -
> ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
> "Acquired hardware Global Lock\n"));
> break;
> }
>
> - acpi_ev_global_lock_pending = TRUE;
> -
> - acpi_os_release_lock(acpi_ev_global_lock_pending_lock, flags);
> -
> /*
> - * Did not get the lock. The pending bit was set above, and we
> - * must wait until we get the global lock released interrupt.
> + * Did not get the lock. The pending bit was set above, and
> + * we must now wait until we receive the global lock
> + * released interrupt.
> */
> + acpi_gbl_global_lock_pending = TRUE;
> + acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags);
> +
> ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
> "Waiting for hardware Global Lock\n"));
>
> @@ -496,17 +503,16 @@ acpi_status acpi_ev_acquire_global_lock(u16 timeout)
> * Wait for handshake with the global lock interrupt handler.
> * This interface releases the interpreter if we must wait.
> */
> - status = acpi_ex_system_wait_semaphore(
> - acpi_gbl_global_lock_semaphore,
> - ACPI_WAIT_FOREVER);
> + status =
> + acpi_ex_system_wait_semaphore
> + (acpi_gbl_global_lock_semaphore, ACPI_WAIT_FOREVER);
>
> - flags = acpi_os_acquire_lock(acpi_ev_global_lock_pending_lock);
> + flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock);
>
> } while (ACPI_SUCCESS(status));
>
> - acpi_ev_global_lock_pending = FALSE;
> -
> - acpi_os_release_lock(acpi_ev_global_lock_pending_lock, flags);
> + acpi_gbl_global_lock_pending = FALSE;
> + acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags);
>
> return_ACPI_STATUS(status);
> }
> diff --git a/drivers/acpi/acpica/utmutex.c b/drivers/acpi/acpica/utmutex.c
> index 519d4ee..7d797e2 100644
> --- a/drivers/acpi/acpica/utmutex.c
> +++ b/drivers/acpi/acpica/utmutex.c
> @@ -93,11 +93,6 @@ acpi_status acpi_ut_mutex_initialize(void)
> return_ACPI_STATUS (status);
> }
>
> - status = acpi_os_create_lock (&acpi_ev_global_lock_pending_lock);
> - if (ACPI_FAILURE (status)) {
> - return_ACPI_STATUS (status);
> - }
> -
> /* Mutex for _OSI support */
> status = acpi_os_create_mutex(&acpi_gbl_osi_mutex);
> if (ACPI_FAILURE(status)) {
>
--
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