On Wednesday, August 16, 2017 3:16:59 AM CEST Srinivas Pandruvada wrote: > For SoC to achieve its lowest power platform idle state a set of hardware > preconditions must be met. These preconditions or constraints can be > obtained by issuing a device specific method (_DSM) with function "1". > Refer to the document provided in the link below. > > Here during initialization (from attach() callback of LPS0 device), invoke > function 1 to get the device constraints. Each enabled constraint is > stored in a table. > > The devices in this table are used to check whether they were in required > minimum state, while entering suspend. This check is done from platform > freeze wake() callback, only when /sys/power/pm_debug_messages attribute > is non zero. > > If any constraint is not met and device is ACPI power managed then it > prints the device information to kernel logs. > > Also if debug is enabled in acpi/sleep.c, the constraint table and state > of each device on wake is dumped in kernel logs. > > Since pm_debug_messages_on setting is used as condition to check > constraints outside kernel/power/main.c, pm_debug_messages_on is changed > to a global variable. > > Link: http://www.uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf > Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx> Applied, thanks! -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
