On Friday 23 January 2015 08:36 AM, Michael Ellerman wrote:
> On Mon, 2015-01-19 at 13:35 +0530, Shreyas B. Prabhu wrote:
>> PECE1 bit in LPCR is used to control whether decrementer can cause exit
>> from powersaving states. PECE1 bit is cleared before entering fastsleep
>> or deeper powersaving state and it is set on waking up. Since both
>> cpuidle and cpu offline operations use these powersaving states, add
>> helper functions to be used in both these places.
>
> Thanks.
>
> That isn't really much clearer than the original, so in the end I just merged
> your original fix.
>
> I'll think if there's a bigger consolidation we can do that makes it clearer.
>
> cheers
>
>
Helper could have been this :
#define LPCR_CLEAR_PECE1 (mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1)
This perhaps would make it more clearer, but it will end up using additional
mfspr here-
static int fastsleep_loop(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
...
new_lpcr = old_lpcr;
/* Do not exit powersave upon decrementer as we've setup the timer
* offload.
*/
new_lpcr &= ~LPCR_PECE1;
mtspr(SPRN_LPCR, new_lpcr);
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