Messages in this thread |  | | From | Sudeep Holla <> | Subject | Re: [PATCH v7 2/6] ACPI / processor_idle: Add support for Low Power Idle(LPI) states | Date | Mon, 4 Jul 2016 14:00:03 +0100 |
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On 01/07/16 14:07, Daniel Lezcano wrote: > On 06/28/2016 03:55 PM, Sudeep Holla wrote: >> ACPI 6.0 introduced an optional object _LPI that provides an alternate >> method to describe Low Power Idle states. It defines the local power >> states for each node in a hierarchical processor topology. The OSPM can >> use _LPI object to select a local power state for each level of processor >> hierarchy in the system. They used to produce a composite power state >> request that is presented to the platform by the OSPM. >> >> Since multiple processors affect the idle state for any non-leaf >> hierarchy >> node, coordination of idle state requests between the processors is >> required. ACPI supports two different coordination schemes: Platform >> coordinated and OS initiated. >> >> This patch adds initial support for Platform coordination scheme of LPI. >> >> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> >> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> >> --- > > Hi Sudeep, > > I looked at the acpi processor idle code sometime ago and from my POV, > it was awful, unnecessary complex and very difficult to maintain. The > usage of flags all over the places is significant of the lack of control > of the written code. >
So you have any specific things in mind ? That's too broad and I know it's not so clean, but it's so for legacy reasons. I would leave that to Rafael to decide as it takes lots of testing to clean up these code.
> Even if you are not responsible of this implementation, the current > situation forces you to add more awful code on top of that, which is > clearly against "making Linux better". >
OK
> IMO, the current code deserves a huge cleanup before applying anything > new : cstate and lpi should be investigated to be self-contained in > their respective file and consolidated, the global variable usage should > be killed, redundant flag checking removed by recapturing the code flow, > etc ... I believe the usage of acpi probe table could be one entry point > to begin this cleanup. >
This is not a static table.
-- Regards, Sudeep
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