Re: [linux-pm] [PATCH] PowerOP, PowerOP Core, 1/2

["Eugeny S. Mints" <eugeny.mints@gmail.com>]

Scott E. Preece wrote:
> | From: Pavel Machek<pavel@ucw.cz>
> | 
> | > >>+struct powerop_driver {
> | > >>+	char *name;
> | > >>+	void *(*create_point) (const char *pwr_params, va_list args);
> | > >>+	int (*set_point) (void *md_opt);
> | > >>+	int (*get_point) (void *md_opt, const char *pwr_params, va_list 
> | > >>args);
> | > >>+};
> | > >
> | > >We can certainly get better interface than va_list, right?
> | > 
> | > Please elaborate.
> | 
> | va_list does not provide adequate type checking. I do not think it
> | suitable in driver<->core interface.
> ---
> 
> Well, in this particular case the typing probably has to be weak, one
> way or another. The meaning of the parameters is arguably opaque at
> the interface - the attributes may be meaningful to specific components
> of the system, but are not defined in the standardized interface (which
> would otherwise have to know about all possible kinds of power
> attributes and be changed every time a new one is added).
> 
> So, if you'd rather have an array of char* or void* values, that would
> probably also meet the need, but my guess is that the typing is
> intentionally opaque.

exactly. Thanks Scott, I don't have anything meaningful to add here.

> ---
> | ...
> | > >How is it going to work on 8cpu box? will
> | > >you have states like cpu1_800MHz_cpu2_1600MHz_cpu3_800MHz_... ?
> | > 
> | > i do not operate with term 'state' so I don't understand what it means here.
> | 
> | Okay, state here means "operating point". How will operating points
> | look on 8cpu box? That's 256 states if cpus only support "low" and
> | "high". How do you name them?
> ---
> 
> I don't think you would name the compounded states. Each CPU would need
> to have its own defined set of operating points (since the capabilities
> of the CPUs can reasonably be different).

i'm not sure - may be it's the mail list issues but in fact I sent out
my additional comment on this question in a separate letter on this thread
a while ago.

Eugeny

> scott