On Thursday, May 10, 2012, Daniel Drake wrote:
> When the system is woken up by the ACPI fixed power button, currently there
> is no way of userspace becoming aware that the power button was pressed.
>
> OLPC would like to know this, so that we can respond appropriately.
> For example, if the system was woken up by a network packet, we know
> we can go back to sleep very quickly. But if the user explicitly woke the
> system with the power button, we're going to want to stay awake for a
> while.
>
> The wakeup count mechanism seems like a good fit for communicating this.
> Mark the fixed power button as wakeup-enabled, and increment its wakeup
> counter when the system is woken with the power button. (The wakeup counter
> is also incremented when the power button is pressed during system
> operation; this is already handled by an existing acpi-button codepath).
>
> Signed-off-by: Daniel Drake <dsd@xxxxxxxxxx>
> Acked-by: Zhang Rui <rui.zhang@xxxxxxxxx>
Acked-by: Rafael J. Wysocki <rjw@xxxxxxx>
Len, this looks like v3.5 material to me, any chance to pick it up?
Rafael
> ---
> drivers/acpi/scan.c | 1 +
> drivers/acpi/sleep.c | 45 +++++++++++++++++++++++++++++++++++++++++++--
> 2 files changed, 44 insertions(+), 2 deletions(-)
>
> v2: add missing put_device() call
> Resending after 3 weeks with no response.
>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index 7417267..06d2135 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -1563,6 +1563,7 @@ static int acpi_bus_scan_fixed(void)
> ACPI_BUS_TYPE_POWER_BUTTON,
> ACPI_STA_DEFAULT,
> &ops);
> + device_init_wakeup(&device->dev, true);
> }
>
> if ((acpi_gbl_FADT.flags & ACPI_FADT_SLEEP_BUTTON) == 0) {
> diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
> index eb6fd23..a564fc3 100644
> --- a/drivers/acpi/sleep.c
> +++ b/drivers/acpi/sleep.c
> @@ -57,6 +57,7 @@ MODULE_PARM_DESC(gts, "Enable evaluation of _GTS on suspend.");
> MODULE_PARM_DESC(bfs, "Enable evaluation of _BFS on resume".);
>
> static u8 sleep_states[ACPI_S_STATE_COUNT];
> +static bool pwr_btn_event_pending;
>
> static void acpi_sleep_tts_switch(u32 acpi_state)
> {
> @@ -186,6 +187,14 @@ static int acpi_pm_prepare(void)
> return error;
> }
>
> +static int find_powerf_dev(struct device *dev, void *data)
> +{
> + struct acpi_device *device = to_acpi_device(dev);
> + const char *hid = acpi_device_hid(device);
> +
> + return !strcmp(hid, ACPI_BUTTON_HID_POWERF);
> +}
> +
> /**
> * acpi_pm_finish - Instruct the platform to leave a sleep state.
> *
> @@ -194,6 +203,7 @@ static int acpi_pm_prepare(void)
> */
> static void acpi_pm_finish(void)
> {
> + struct device *pwr_btn_dev;
> u32 acpi_state = acpi_target_sleep_state;
>
> acpi_ec_unblock_transactions();
> @@ -211,6 +221,23 @@ static void acpi_pm_finish(void)
> acpi_set_firmware_waking_vector((acpi_physical_address) 0);
>
> acpi_target_sleep_state = ACPI_STATE_S0;
> +
> + /* If we were woken with the fixed power button, provide a small
> + * hint to userspace in the form of a wakeup event on the fixed power
> + * button device (if it can be found).
> + *
> + * We delay the event generation til now, as the PM layer requires
> + * timekeeping to be running before we generate events. */
> + if (!pwr_btn_event_pending)
> + return;
> +
> + pwr_btn_event_pending = false;
> + pwr_btn_dev = bus_find_device(&acpi_bus_type, NULL, NULL,
> + find_powerf_dev);
> + if (pwr_btn_dev) {
> + pm_wakeup_event(pwr_btn_dev, 0);
> + put_device(pwr_btn_dev);
> + }
> }
>
> /**
> @@ -300,9 +327,23 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
> /* ACPI 3.0 specs (P62) says that it's the responsibility
> * of the OSPM to clear the status bit [ implying that the
> * POWER_BUTTON event should not reach userspace ]
> + *
> + * However, we do generate a small hint for userspace in the form of
> + * a wakeup event. We flag this condition for now and generate the
> + * event later, as we're currently too early in resume to be able to
> + * generate wakeup events.
> */
> - if (ACPI_SUCCESS(status) && (acpi_state == ACPI_STATE_S3))
> - acpi_clear_event(ACPI_EVENT_POWER_BUTTON);
> + if (ACPI_SUCCESS(status) && (acpi_state == ACPI_STATE_S3)) {
> + acpi_event_status pwr_btn_status;
> +
> + acpi_get_event_status(ACPI_EVENT_POWER_BUTTON, &pwr_btn_status);
> +
> + if (pwr_btn_status & ACPI_EVENT_FLAG_SET) {
> + acpi_clear_event(ACPI_EVENT_POWER_BUTTON);
> + /* Flag for later */
> + pwr_btn_event_pending = true;
> + }
> + }
>
> /*
> * Disable and clear GPE status before interrupt is enabled. Some GPEs
>
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