This patch adds a timer to poll EC events: 1. between acpi_ec_suspend() and acpi_ec_block_transactions(), 2. between acpi_ec_unblock_transactions() and acpi_ec_resume(). During these periods, if an EC event occurred, we have not mean to detect it. Thus the events occurred in late S3-entry could be dropped, and the events occurred in early S3-exit could be deferred to acpi_ec_resume().
This patch solves event losses in S3-entry and resume order in S3-exit by timely polling EC events during these periods. Link: https://bugzilla.kernel.org/show_bug.cgi?id=196129 [#1] Signed-off-by: Lv Zheng <lv.zh...@intel.com> Tested-by: Tomislav Ivek <tomislav.i...@gmail.com> --- drivers/acpi/ec.c | 93 +++++++++++++++++++++++++++++++++++++++++++++++-- drivers/acpi/internal.h | 1 + 2 files changed, 92 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c index f1f320b..389c499 100644 --- a/drivers/acpi/ec.c +++ b/drivers/acpi/ec.c @@ -40,6 +40,7 @@ #include <linux/slab.h> #include <linux/acpi.h> #include <linux/dmi.h> +#include <linux/timer.h> #include <asm/io.h> #include "internal.h" @@ -102,6 +103,7 @@ enum ec_command { #define ACPI_EC_CLEAR_MAX 100 /* Maximum number of events to query * when trying to clear the EC */ #define ACPI_EC_MAX_QUERIES 16 /* Maximum number of parallel queries */ +#define ACPI_EC_EVENT_INTERVAL 500 /* Detecting event every 500ms */ enum { EC_FLAGS_QUERY_ENABLED, /* Query is enabled */ @@ -113,6 +115,7 @@ enum { EC_FLAGS_STARTED, /* Driver is started */ EC_FLAGS_STOPPED, /* Driver is stopped */ EC_FLAGS_GPE_MASKED, /* GPE masked */ + EC_FLAGS_GPE_POLLING, /* GPE polling is enabled */ }; #define ACPI_EC_COMMAND_POLL 0x01 /* Available for command byte */ @@ -154,6 +157,15 @@ static bool ec_no_wakeup __read_mostly; module_param(ec_no_wakeup, bool, 0644); MODULE_PARM_DESC(ec_no_wakeup, "Do not wake up from suspend-to-idle"); +static bool ec_detect_noirq_events __read_mostly; +module_param(ec_detect_noirq_events, bool, 0644); +MODULE_PARM_DESC(ec_detect_noirq_events, "Enabling event detection during noirq stage"); + +static unsigned int +ec_detect_noirq_interval __read_mostly = ACPI_EC_EVENT_INTERVAL; +module_param(ec_detect_noirq_interval, uint, 0644); +MODULE_PARM_DESC(ec_detect_noirq_interval, "Event detection interval(ms) during noirq stage"); + struct acpi_ec_query_handler { struct list_head node; acpi_ec_query_func func; @@ -358,6 +370,48 @@ static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec) return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false; } +static void acpi_ec_gpe_tick(struct acpi_ec *ec) +{ + mod_timer(&ec->timer, + jiffies + msecs_to_jiffies(ec_detect_noirq_interval)); +} + +static void ec_start_gpe_poller(struct acpi_ec *ec) +{ + unsigned long flags; + bool start_tick = false; + + if (!acpi_ec_no_sleep_events() || !ec_detect_noirq_events) + return; + spin_lock_irqsave(&ec->lock, flags); + if (!test_and_set_bit(EC_FLAGS_GPE_POLLING, &ec->flags)) { + ec_log_drv("GPE poller started"); + start_tick = true; + /* kick off GPE polling without delay */ + advance_transaction(ec); + } + spin_unlock_irqrestore(&ec->lock, flags); + if (start_tick) + acpi_ec_gpe_tick(ec); +} + +static void ec_stop_gpe_poller(struct acpi_ec *ec) +{ + unsigned long flags; + bool stop_tick = false; + + if (!acpi_ec_no_sleep_events() || !ec_detect_noirq_events) + return; + spin_lock_irqsave(&ec->lock, flags); + if (test_and_clear_bit(EC_FLAGS_GPE_POLLING, &ec->flags)) + stop_tick = true; + spin_unlock_irqrestore(&ec->lock, flags); + if (stop_tick) { + del_timer_sync(&ec->timer); + ec_log_drv("GPE poller stopped"); + } +} + static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open) { if (open) @@ -1017,6 +1071,12 @@ static void acpi_ec_leave_noirq(struct acpi_ec *ec) spin_unlock_irqrestore(&ec->lock, flags); } +/* + * Note: this API is prepared for tuning the order of the ACPI + * suspend/resume steps as the last entry of EC during suspend, thus it + * must be invoked after acpi_ec_suspend() or everything should be done in + * acpi_ec_suspend(). + */ void acpi_ec_block_transactions(void) { struct acpi_ec *ec = first_ec; @@ -1028,16 +1088,28 @@ void acpi_ec_block_transactions(void) /* Prevent transactions from being carried out */ acpi_ec_stop(ec, true); mutex_unlock(&ec->mutex); + ec_stop_gpe_poller(ec); } +/* + * Note: this API is prepared for tuning the order of the ACPI + * suspend/resume steps as the first entry of EC during resume, thus it + * must be invoked before acpi_ec_resume() or everything should be done in + * acpi_ec_resume(). + */ void acpi_ec_unblock_transactions(void) { + struct acpi_ec *ec = first_ec; + + if (!ec) + return; + + ec_start_gpe_poller(ec); /* * 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) - acpi_ec_start(first_ec, true); + acpi_ec_start(ec, true); } /* -------------------------------------------------------------------------- @@ -1278,6 +1350,19 @@ static u32 acpi_ec_gpe_handler(acpi_handle gpe_device, return ACPI_INTERRUPT_HANDLED; } +static void acpi_ec_gpe_poller(ulong arg) +{ + struct acpi_ec *ec = (struct acpi_ec *)arg; + unsigned long flags; + + spin_lock_irqsave(&ec->lock, flags); + ec_dbg_drv("GPE polling begin"); + advance_transaction(ec); + ec_dbg_drv("GPE polling end"); + spin_unlock_irqrestore(&ec->lock, flags); + acpi_ec_gpe_tick(ec); +} + /* -------------------------------------------------------------------------- * Address Space Management * -------------------------------------------------------------------------- */ @@ -1347,6 +1432,8 @@ static struct acpi_ec *acpi_ec_alloc(void) INIT_LIST_HEAD(&ec->list); spin_lock_init(&ec->lock); INIT_WORK(&ec->work, acpi_ec_event_handler); + init_timer(&ec->timer); + setup_timer(&ec->timer, acpi_ec_gpe_poller, (ulong)ec); ec->timestamp = jiffies; ec->busy_polling = true; ec->polling_guard = 0; @@ -1918,6 +2005,7 @@ static int acpi_ec_suspend(struct device *dev) if (acpi_ec_no_sleep_events()) acpi_ec_disable_event(ec); + ec_start_gpe_poller(ec); return 0; } @@ -1952,6 +2040,7 @@ static int acpi_ec_resume(struct device *dev) struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev)); + ec_stop_gpe_poller(ec); if (acpi_ec_no_sleep_events()) acpi_ec_enable_event(ec); else { diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h index ede83d3..708b379 100644 --- a/drivers/acpi/internal.h +++ b/drivers/acpi/internal.h @@ -171,6 +171,7 @@ struct acpi_ec { struct transaction *curr; spinlock_t lock; struct work_struct work; + struct timer_list timer; unsigned long timestamp; unsigned long nr_pending_queries; bool busy_polling; -- 2.7.4
