> -----Original Message----- > From: Jarkko Nikula [mailto:[email protected]] > Sent: Wednesday, April 13, 2011 7:13 AM > To: Vishwanath BS > Cc: [email protected]; [email protected]; Santosh > Shilimkar > Subject: Re: [PATCH 08/13] OMAP3: cpufreq driver changes for DVFS > support > > Hi > > A few comments below in case this is still under development as I > was > playing a bit with this version on omap3. There is an updated version of omap cpufreq patches where this issue is fixed. https://patchwork.kernel.org/patch/632781/
Regards Vishwa > > On Fri, 21 Jan 2011 19:31:00 +0530 > Vishwanath BS <[email protected]> wrote: > > > Changes in the omap cpufreq driver for DVFS support. > > > > Signed-off-by: Vishwanath BS <[email protected]> > > Cc: Santosh Shilimkar <[email protected]> > > --- > > arch/arm/plat-omap/cpu-omap.c | 35 > ++++++++++++++++++++++++++++++++--- > > 1 files changed, 32 insertions(+), 3 deletions(-) > > > ... > > @@ -85,11 +87,11 @@ static int omap_target(struct cpufreq_policy > *policy, > > unsigned int target_freq, > > unsigned int relation) > > { > > -#ifdef CONFIG_ARCH_OMAP1 > > struct cpufreq_freqs freqs; > > -#endif > > #if defined(CONFIG_ARCH_OMAP3) && !defined(CONFIG_OMAP_PM_NONE) > > unsigned long freq; > > + int i; > > + struct cpufreq_freqs freqs_notify; > > struct device *mpu_dev = omap2_get_mpuss_device(); > > #endif > > int ret = 0; > > @@ -116,9 +118,36 @@ static int omap_target(struct cpufreq_policy > *policy, > > ret = clk_set_rate(mpu_clk, freqs.new * 1000); > > cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); > > #elif defined(CONFIG_ARCH_OMAP3) && !defined(CONFIG_OMAP_PM_NONE) > > + freqs.old = omap_getspeed(policy->cpu);; > > + freqs_notify.new = clk_round_rate(mpu_clk, target_freq * 1000) > / 1000; > > + freqs.cpu = policy->cpu; > > + > > + if (freqs.old == freqs.new) > > + return ret; > > + > > Here freqs.new is uninitialized which very likely means that code > falls > always through, sets the correct target frequency though, but can > populate the wrong frequency through the cpufreq_notify_transition > when > running the pre notifiers below. > > I think the code above meant > > freqs_notify.new = clk_round_rate(mpu_clk, target_freq * 1000) / > 1000; > -> > freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000; > > as the freqs_notify is otherwise unused? > > However, that doesn't work as the clk_round_rate returns the current > rate for mpu_clk on omap3 and "freqs.old == freqs.new" is always > true. > Looks like there is no round_rate function for arm_fck. > > I replaced that with "freqs.new = target_freq;" but this means there > will be unnecessary fall throughs if the real frequency (eg 124800 > kHz) > will differ from opp table frequency (eg 125000 kHz) and no real > changes are happening e.g. with on-demand governor. > > > + /* pre notifiers */ > > + for_each_cpu(i, policy->cpus) { > > + freqs.cpu = i; > > + cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); > > + } > > -- > Jarkko -- 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
