diff options
| author | Lv Zheng <lv.zheng@intel.com> | 2016-08-03 09:07:58 +0800 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-08-17 02:37:02 +0200 |
| commit | df45db6177f8dde380d44149cca46ad800a00575 (patch) | |
| tree | cb42fc57f30847b2b38b19e3790e50ff140f5592 /drivers | |
| parent | 694d0d0bb2030d2e36df73e2d23d5770511dbc8d (diff) | |
| download | linux-df45db6177f8dde380d44149cca46ad800a00575.tar.bz2 | |
ACPI / EC: Add PM operations for suspend/resume noirq stage
It is reported that on some platforms, resume speed is not fast. The cause
is: in noirq stage, EC driver is working in polling mode, and each state
machine advancement requires a context switch.
The context switch is not necessary to the EC driver's polling mode. This
patch implements PM hooks to automatically switch the driver to/from the
busy polling mode to eliminate the overhead caused by the context switch.
This finally contributes to the tuning result: acpi_pm_finish() execution
time is improved from 192ms to 6ms.
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Reported-and-tested-by: Todd E Brandt <todd.e.brandt@linux.intel.com>
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/acpi/ec.c | 53 | ||||
| -rw-r--r-- | drivers/acpi/internal.h | 2 |
2 files changed, 55 insertions, 0 deletions
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c index e7bd57cc550a..6f6c7d1eaf8c 100644 --- a/drivers/acpi/ec.c +++ b/drivers/acpi/ec.c @@ -1619,6 +1619,58 @@ error: return ret; } +#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 = + acpi_driver_data(to_acpi_device(dev)); + + acpi_ec_enter_noirq(ec); + return 0; +} + +static int acpi_ec_resume_noirq(struct device *dev) +{ + struct acpi_ec *ec = + acpi_driver_data(to_acpi_device(dev)); + + acpi_ec_leave_noirq(ec); + return 0; +} +#endif + +static const struct dev_pm_ops acpi_ec_pm = { + SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq) +}; + static int param_set_event_clearing(const char *val, struct kernel_param *kp) { int result = 0; @@ -1664,6 +1716,7 @@ static struct acpi_driver acpi_ec_driver = { .add = acpi_ec_add, .remove = acpi_ec_remove, }, + .drv.pm = &acpi_ec_pm, }; static inline int acpi_ec_query_init(void) diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h index 940218ff0193..6996121ee003 100644 --- a/drivers/acpi/internal.h +++ b/drivers/acpi/internal.h @@ -174,6 +174,8 @@ struct acpi_ec { struct work_struct work; unsigned long timestamp; unsigned long nr_pending_queries; + bool saved_busy_polling; + unsigned int saved_polling_guard; }; extern struct acpi_ec *first_ec; |