On Fri, Jun 24, 2011 at 04:18:31PM +0530, Premi, Sanjeev wrote:
> > -----Original Message-----
> > From: Russell King - ARM Linux [mailto:[email protected]]
> > Sent: Friday, June 24, 2011 4:14 PM
> > To: Premi, Sanjeev
> > Cc: [email protected]; [email protected]
> > Subject: Re: [PATCH 2/2] omap2+: pm: cpufreq: Fix
> > loops_per_jiffy calculation
> >
> > On Fri, Jun 24, 2011 at 04:05:42PM +0530, Sanjeev Premi wrote:
> > > Currently, loops_per_jiffy is being calculated before calling
> > > cpufreq_notify_transition().
> > >
> > > However, generic cpufreq driver adjusts the jiffies as well.
> > > Double adjustment leads to incorrect value being assigned to
> > > loops_per_jiffy.
> >
> > Are you sure the generic cpufreq driver adjusts the per-cpu
> > loops_per_jiffy
> > values? I don't believe it does.
>
> Russell,
>
> I am quoting the function from drivers/cpufreq/cpufreq.h
> Follow the arrows:
Let's go to war with quotes then, because clearly you haven't read the code
properly:
| #ifndef CONFIG_SMP
^^^^^^^^^^^^^^^^^^^^^
| static unsigned long l_p_j_ref;
| static unsigned int l_p_j_ref_freq;
|
| static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
| {
| ... code to adjust jiffies ...
| }
| #else
| static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
| {
| return;
| }
| #endif
Notice how if CONFIG_SMP is set, adjust_jiffies becomes a no-op. So if
CONFIG_SMP=y, loops_per_jiffy will _not_ be scaled by core code.
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
