Re: [PATCH 0/2] cpufreq/opp: rework regulator initialization

From: Marek Szyprowski
Date: Fri Feb 08 2019 - 06:47:13 EST

Hi Sudeep,

On 2019-02-08 12:00, Sudeep Holla wrote:
> On Thu, Feb 07, 2019 at 01:22:25PM +0100, Marek Szyprowski wrote:
>> Dear All,
>> This is a scenario that triggers the above issue:
> [...]
>> 1. system disables non-boot cpu's at the end of system suspend procedure,
>> 2. this in turn deinitializes cpufreq drivers for the disabled cpus,
>> 3. early in the system resume procedure all cpus are got back to online
>> state,
>> 4. this in turn causes cpufreq to be initialized for the newly onlined
>> cpus,
>> 5. cpufreq-dt acquires all its resources (clocks, regulators) during
>> ->init() callback,
> This is strictly not just restricted to cpufreq-dt, but to any driver
> supporting multiple policies. So we need a generic fix not just
> cpufreq-dt specific.

Could you point which other driver needs similar fix? Here in cpufreq-dt
the problem was caused by using regulator api (indirectly) from
->init(). All other drivers, which have regulators support, are for old,
obsolete, uni-processor systems, which don't have the problem of
secondary cpu suspend during system suspend/resume cycle.

Best regards
Marek Szyprowski, PhD
Samsung R&D Institute Poland