On Thu, 2022-03-10 at 09:17 -0600, Mario Limonciello wrote:
> If constraints checking has been enabled by the LPS0 code, it may
> also be useful for drivers using the callback to make a decision what
> to do.
>
> For example this may in the future allow a failing constraints check
> preventing another driver from notifying firmware that all required
> devices have entered the deepest state.
>
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> ---
> drivers/acpi/x86/s2idle.c | 17 ++++++++++-------
> include/linux/acpi.h | 4 ++--
> 2 files changed, 12 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/acpi/x86/s2idle.c b/drivers/acpi/x86/s2idle.c
> index 652dc2d75458..c737a8e5d5a5 100644
> --- a/drivers/acpi/x86/s2idle.c
> +++ b/drivers/acpi/x86/s2idle.c
> @@ -88,7 +88,7 @@ struct lpi_device_constraint_amd {
>
> struct lps0_callback_handler {
> struct list_head list_node;
> - int (*prepare_late_callback)(void *context);
> + int (*prepare_late_callback)(void *context, bool constraints);
> void (*restore_early_callback)(void *context);
> void *context;
> };
> @@ -297,7 +297,7 @@ static void lpi_device_get_constraints(void)
> ACPI_FREE(out_obj);
> }
>
> -static void lpi_check_constraints(void)
> +static void lpi_check_constraints(bool *met)
> {
> int i;
>
> @@ -319,11 +319,13 @@ static void lpi_check_constraints(void)
> continue;
> }
>
> - if (adev->power.state < lpi_constraints_table[i].min_dstate)
> + if (adev->power.state < lpi_constraints_table[i].min_dstate) {
> acpi_handle_info(handle,
> "LPI: Constraint not met; min power state:%s
> current power state:%s\n",
> acpi_power_state_string(lpi_constraints_table[i]
> .min_dstate),
> acpi_power_state_string(adev->power.state));
> + *met = false;
> + }
> }
> }
>
> @@ -455,13 +457,14 @@ static struct acpi_scan_handler lps0_handler = {
> int acpi_s2idle_prepare_late(void)
> {
> struct lps0_callback_handler *handler;
> + bool constraints_met = true;
> int rc = 0;
>
> if (!lps0_device_handle || sleep_no_lps0)
> return 0;
>
> if (pm_debug_messages_on)
> - lpi_check_constraints();
> + lpi_check_constraints(&constraints_met);
lpi_check_constraints() was only used for dumping information to dmesg. If you
want to make a decision based on whether a constraint was met then you probably
want to run it all the time. You could use pm_debug_messages_on inside of
lpi_check_contraints() to decide whether to print to the log.
>
> /* Screen off */
> if (lps0_dsm_func_mask > 0)
> @@ -490,7 +493,7 @@ int acpi_s2idle_prepare_late(void)
>
> mutex_lock(&lps0_callback_handler_mutex);
> list_for_each_entry(handler, &lps0_callback_handler_head, list_node) {
> - rc = handler->prepare_late_callback(handler->context);
> + rc = handler->prepare_late_callback(handler->context,
> constraints_met);
Otherwise, is it okay that constraints_met will always be true if
pm_debug_messages_on isn't?
David
> if (rc)
> goto out;
> }
> @@ -554,7 +557,7 @@ void acpi_s2idle_setup(void)
> s2idle_set_ops(&acpi_s2idle_ops_lps0);
> }
>
> -int acpi_register_lps0_callbacks(int (*prepare_late)(void *context),
> +int acpi_register_lps0_callbacks(int (*prepare_late)(void *context, bool
> constraints),
> void (*restore_early)(void *context),
> void *context)
> {
> @@ -578,7 +581,7 @@ int acpi_register_lps0_callbacks(int (*prepare_late)(void
> *context),
> }
> EXPORT_SYMBOL_GPL(acpi_register_lps0_callbacks);
>
> -void acpi_unregister_lps0_callbacks(int (*prepare_late)(void *context),
> +void acpi_unregister_lps0_callbacks(int (*prepare_late)(void *context, bool
> constraints),
> void (*restore_early)(void *context),
> void *context)
> {
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index cae0fde309f2..5aae774670dc 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -1024,10 +1024,10 @@ void acpi_os_set_prepare_extended_sleep(int (*func)(u8
> sleep_state,
> acpi_status acpi_os_prepare_extended_sleep(u8 sleep_state,
> u32 val_a, u32 val_b);
> #ifdef CONFIG_X86
> -int acpi_register_lps0_callbacks(int (*prepare_late)(void *context),
> +int acpi_register_lps0_callbacks(int (*prepare_late)(void *context, bool
> constraints),
> void (*restore_early)(void *context),
> void *context);
> -void acpi_unregister_lps0_callbacks(int (*prepare_late)(void *context),
> +void acpi_unregister_lps0_callbacks(int (*prepare_late)(void *context, bool
> constraints),
> void (*restore_early)(void *context),
> void *context);
> #endif /* CONFIG_X86 */
