Re: Implementing PowerManagment for a ppc target

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Tue, 2004-11-30 at 22:40 +0100, Sylvain Munaut wrote:
> Hi,
> 
> I'm trying to implement Deep Sleep support for a ppc platform based on 
> 5200 and I have some questions :
> 
>  - How should I "integrate" it to linux, what the proper way ? I've been 
> trying #defining CONFIG_PM and
>    using the set_pm_ops operation but my call backs never get called 
> when doing a echo standby > /sys/power/state
> 
> It justs says :
> 
> $ echo standby > 
> /sys/power/state                                                                     
> 
> Stopping tasks: 
> ===                                                                                   

Looks like a kernel thread isn't properly stopping ... note that on
pmac, I don't call that PM core, I do my own salad which does not
involve stopping tasks...

>  stopping tasks failed (2 tasks 
> remaining)                                                           
> Restarting tasks...<6> Strange, init not 
> stopped                                                     
>  Strange, sh not 
> stopped                                                                              
> 
>  done                                                                                                 
> 
> Stopping tasks: 
> ===                                                                                   
> 
>  stopping tasks failed (2 tasks 
> remaining)                                                           
> Restarting tasks...<6> Strange, init not 
> stopped                                                     
>  Strange, sh not 
> stopped                                                                              
> 
>  done                 
> 
> I've been trying to look at Documentation/ and the sources but still I'm 
> not sure ...
> 
> 
>  - How can I ensure that one of my function runs out of I Cache ? Some 
> pieces of assembler needs to not
>    acces memory when the last 'orders' are sent. Does just keeping it 
> small and aligned enough ?

Can you explain more precisely why and what are your precise
requirements ? (You can catch me on irc eventually) 
 
> 
> Thanks,
> 
>     Sylvain Munaut
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-- 
Benjamin Herrenschmidt <benh@kernel.crashing.org>