Re: [PATCH] OMAP2+: CPUfreq: Allow the CPU scaling when secondary CPUs are offline.

[Kevin Hilman <khilman@ti.com>]

Santosh Shilimkar <santosh.shilimkar@ti.com> writes:

> Current OMAP2PLUS CPUfreq tagret() functions returns when all
> the CPU's are not online. This will break DVFS when secondary
> CPUs are offlined.
>
> The intention of that check was just avoid CPU frequency change
> during the window when CPU becomes online but it's cpufreq_init is
> not done yet.
>
> Fix the check accordingly.
>
> Thanks for Nishant Menon <nm@ti.com> for reporting it.
>
> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
> Reported-by: Nishanth Menon <nm@ti.com>
> Tested-by: Vishwanath BS <vishwanath.bs@ti.com>
> ---
> There were some question of making the variable atomic etc
> in an internal discussion. After some thinking, I realised
> there is no need of that since this is just a counter which
> maintains the count for online_cpus = cpufreq_init_cpus. 

Since this is init-time only check, the check for every call to
->target() seems excessive.

How about leaving the ->target callback empty until all the CPUs are
online.

Also, how will this handle an SMP kernel booted with maxcpus=1 on the
cmdline?

Kevin