Re: [PATCH] ACPICA: Enable sleep button on ACPI legacy wake

["Rafael J. Wysocki" <rjw@rjwysocki.net>]

On Monday, October 29, 2018 6:52:16 PM CET Anchal Agarwal wrote:
> Currently we do not see sleep_enable bit set after guest resumes
> from hibernation. Hibernation is triggered in guest on receiving
> a sleep trigger from the hypervisor(S4 state). We see that power
> button is enabled on wake up from S4 state however sleep button
> isn't.

I'm not against this change in principle, although it may change behavior
in a somewhat unexpected way on some systems.

> This causes subsequent invocation of sleep state to fail
> in the guest.

However, can you explain this in a bit more detail?
 
> Signed-off-by: Anchal Agarwal <anchalag@amazon.com>
> Reviewed-by: Balbir Singh <sblbir@amazon.com>
> Reviewed-by: Frank van der Linden <fllinden@amazon.com>
> ---
>  drivers/acpi/acpica/hwsleep.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/acpi/acpica/hwsleep.c b/drivers/acpi/acpica/hwsleep.c
> index b62db8ec446f..a176c7802760 100644
> --- a/drivers/acpi/acpica/hwsleep.c
> +++ b/drivers/acpi/acpica/hwsleep.c
> @@ -300,6 +300,17 @@ acpi_status acpi_hw_legacy_wake(u8 sleep_state)
>  				    [ACPI_EVENT_POWER_BUTTON].
>  				    status_register_id, ACPI_CLEAR_STATUS);
>  
> +	/* Enable sleep button */
> +	(void)
> +	      acpi_write_bit_register(acpi_gbl_fixed_event_info
> +				      [ACPI_EVENT_SLEEP_BUTTON].
> +				      enable_register_id, ACPI_ENABLE_EVENT);
> +
> +	(void)
> +	      acpi_write_bit_register(acpi_gbl_fixed_event_info
> +				      [ACPI_EVENT_SLEEP_BUTTON].
> +				      status_register_id, ACPI_CLEAR_STATUS);
> +
>  	acpi_hw_execute_sleep_method(METHOD_PATHNAME__SST, ACPI_SST_WORKING);
>  	return_ACPI_STATUS(status);
>  }
>