From c3a696b6e8f8f75f9f75e556a9f9f6472eae2655 Mon Sep 17 00:00:00 2001 From: Lv Zheng Date: Fri, 20 Jan 2017 16:42:48 +0800 Subject: [PATCH] ACPI / EC: Use busy polling mode when GPE is not enabled When GPE is not enabled, it is not efficient to use the wait polling mode as it introduces an unexpected scheduler delay. So before the GPE handler is installed, this patch uses busy polling mode for all EC(s) and the logic can be applied to non boot EC(s) during the suspend/resume process. Link: https://bugzilla.kernel.org/show_bug.cgi?id=191561 Tested-by: Jakobus Schurz Tested-by: Chen Yu Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki --- drivers/acpi/ec.c | 62 ++++++++++++++++++++--------------------- drivers/acpi/internal.h | 4 +-- 2 files changed, 32 insertions(+), 34 deletions(-) diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c index 6a32cd4ec9da..c24235d8fb52 100644 --- a/drivers/acpi/ec.c +++ b/drivers/acpi/ec.c @@ -704,12 +704,12 @@ static void start_transaction(struct acpi_ec *ec) static int ec_guard(struct acpi_ec *ec) { - unsigned long guard = usecs_to_jiffies(ec_polling_guard); + unsigned long guard = usecs_to_jiffies(ec->polling_guard); unsigned long timeout = ec->timestamp + guard; /* Ensure guarding period before polling EC status */ do { - if (ec_busy_polling) { + if (ec->busy_polling) { /* Perform busy polling */ if (ec_transaction_completed(ec)) return 0; @@ -973,6 +973,28 @@ static void acpi_ec_stop(struct acpi_ec *ec, bool suspending) spin_unlock_irqrestore(&ec->lock, flags); } +static void acpi_ec_enter_noirq(struct acpi_ec *ec) +{ + unsigned long flags; + + spin_lock_irqsave(&ec->lock, flags); + ec->busy_polling = true; + ec->polling_guard = 0; + ec_log_drv("interrupt blocked"); + spin_unlock_irqrestore(&ec->lock, flags); +} + +static void acpi_ec_leave_noirq(struct acpi_ec *ec) +{ + unsigned long flags; + + spin_lock_irqsave(&ec->lock, flags); + ec->busy_polling = ec_busy_polling; + ec->polling_guard = ec_polling_guard; + ec_log_drv("interrupt unblocked"); + spin_unlock_irqrestore(&ec->lock, flags); +} + void acpi_ec_block_transactions(void) { struct acpi_ec *ec = first_ec; @@ -1253,7 +1275,7 @@ acpi_ec_space_handler(u32 function, acpi_physical_address address, if (function != ACPI_READ && function != ACPI_WRITE) return AE_BAD_PARAMETER; - if (ec_busy_polling || bits > 8) + if (ec->busy_polling || bits > 8) acpi_ec_burst_enable(ec); for (i = 0; i < bytes; ++i, ++address, ++value) @@ -1261,7 +1283,7 @@ acpi_ec_space_handler(u32 function, acpi_physical_address address, acpi_ec_read(ec, address, value) : acpi_ec_write(ec, address, *value); - if (ec_busy_polling || bits > 8) + if (ec->busy_polling || bits > 8) acpi_ec_burst_disable(ec); switch (result) { @@ -1304,6 +1326,8 @@ static struct acpi_ec *acpi_ec_alloc(void) spin_lock_init(&ec->lock); INIT_WORK(&ec->work, acpi_ec_event_handler); ec->timestamp = jiffies; + ec->busy_polling = true; + ec->polling_guard = 0; return ec; } @@ -1365,6 +1389,7 @@ static int ec_install_handlers(struct acpi_ec *ec, bool handle_events) acpi_ec_start(ec, false); if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) { + acpi_ec_enter_noirq(ec); status = acpi_install_address_space_handler(ec->handle, ACPI_ADR_SPACE_EC, &acpi_ec_space_handler, @@ -1404,6 +1429,7 @@ static int ec_install_handlers(struct acpi_ec *ec, bool handle_events) /* This is not fatal as we can poll EC events */ if (ACPI_SUCCESS(status)) { set_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags); + acpi_ec_leave_noirq(ec); if (test_bit(EC_FLAGS_STARTED, &ec->flags) && ec->reference_count >= 1) acpi_ec_enable_gpe(ec, true); @@ -1786,34 +1812,6 @@ error: } #ifdef CONFIG_PM_SLEEP -static void acpi_ec_enter_noirq(struct acpi_ec *ec) -{ - unsigned long flags; - - if (ec == first_ec) { - spin_lock_irqsave(&ec->lock, flags); - ec->saved_busy_polling = ec_busy_polling; - ec->saved_polling_guard = ec_polling_guard; - ec_busy_polling = true; - ec_polling_guard = 0; - ec_log_drv("interrupt blocked"); - spin_unlock_irqrestore(&ec->lock, flags); - } -} - -static void acpi_ec_leave_noirq(struct acpi_ec *ec) -{ - unsigned long flags; - - if (ec == first_ec) { - spin_lock_irqsave(&ec->lock, flags); - ec_busy_polling = ec->saved_busy_polling; - ec_polling_guard = ec->saved_polling_guard; - ec_log_drv("interrupt unblocked"); - spin_unlock_irqrestore(&ec->lock, flags); - } -} - static int acpi_ec_suspend_noirq(struct device *dev) { struct acpi_ec *ec = diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h index 0c452265c111..219b90bc0922 100644 --- a/drivers/acpi/internal.h +++ b/drivers/acpi/internal.h @@ -172,8 +172,8 @@ struct acpi_ec { struct work_struct work; unsigned long timestamp; unsigned long nr_pending_queries; - bool saved_busy_polling; - unsigned int saved_polling_guard; + bool busy_polling; + unsigned int polling_guard; }; extern struct acpi_ec *first_ec; -- 2.20.1