On 09/12/2014 10:00 AM, Hanjun Guo wrote: > From: Graeme Gregory <graeme.gregory@xxxxxxxxxx> > > ACPI 5.1 does not currently support S states for ARM64 hardware but > ACPI code will call acpi_target_system_state() for device power > managment, so introduce sleep-arm.c to allow other drivers to function > until S states are defined. Aside: ACPI5.1 does define the Platform Communication Channel and CPC (Collaborative Processor Performance Control). Some details need to be fleshed out there for practical 64-bit ARMv8 server systems, but the underpinnings and mechanisms are in place in the 5.1 specification that can be built upon over time to achieve practical S-State equivalence. Jon. -- 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