[QUERY] AMBA: PM domains when !CONFIG_PM

On 16/06/16 13:33, Ulf Hansson wrote:

On 16 June 2016 at 13:19, Sudeep Holla <sudeep.holla@arm.com
<mailto:sudeep.holla@arm.com>> wrote:

    Hi Ulf, Kevin,

    I have a situation where we need to enable the power domain to access an
    AMBA device. This is all fine with patches from Ulf and Marek in
    amba/bus.c

    The problem is when we disable CONFIG_PM, dev_pm_domain_attach
    returns -ENODEV irrespective of whether a DT node has a PM domain
    in it or not. If dev_pm_domain_attach returns anything other than
    -EPROBE_DEFER, we ignore the error and proceed to access the device
    which will explode.

    Basically, we need a way to prevent addition of that amba device if DT
    node has PD specified but CONFIG_PM=n. Any thoughts ?


The solution TEGRA picked for a kind of similar issue was to enable
CONFIG_PM for a family of SoCs.

I assume this would be applicable here as well, or are you saying this
platform actually is able to work *without* PM support?

I agree, but if someone tries to boot with !CONFIG_PM, it just hangs
without a clue, hence I raised this query. I am fine by forcing it to be
ON always, but just wanted to check if this is something serious that it
needs to be addressed.

Thanks for the quick response.

-- 
Regards,
Sudeep