Messages in this thread | | | Date | Wed, 18 Oct 2017 11:12:42 +0900 | From | Chanwoo Choi <> | Subject | Re: [PATCH v4 3/8] PM / devfreq: Use the available min/max frequency |
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On 2017년 10월 18일 10:31, Chanwoo Choi wrote: > Hi, > > On 2017년 10월 17일 23:43, MyungJoo Ham wrote: >> On Fri, Oct 13, 2017 at 4:48 PM, Chanwoo Choi <cw00.choi@samsung.com> wrote: >>> The commit a76caf55e5b35 ("thermal: Add devfreq cooling") is able >>> to disable OPP as a cooling device. In result, both update_devfreq() >>> and {min|max}_freq_show() have to consider the 'opp->available' >>> status of each OPP. >>> >>> So, this patch adds the 'scaling_{min|max}_freq' to struct devfreq >>> in order to indicate the available mininum and maximum frequency >>> by adjusting OPP interface such as dev_pm_opp_{disable|enable}(). >>> The 'scaling_{min|max}_freq' are used for on both update_devfreq() >>> and {min|max}_freq_show(). >>> >>> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> >>> --- >>> drivers/devfreq/devfreq.c | 36 ++++++++++++++++++++++++++++-------- >>> include/linux/devfreq.h | 4 ++++ >>> 2 files changed, 32 insertions(+), 8 deletions(-) >>> >>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c >>> index b6ba24e5db0d..9de013ffeb67 100644 >>> --- a/drivers/devfreq/devfreq.c >>> +++ b/drivers/devfreq/devfreq.c >> [] >>> @@ -494,6 +499,19 @@ static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type, >>> int ret; >>> >>> mutex_lock(&devfreq->lock); >>> + >>> + devfreq->scaling_min_freq = find_available_min_freq(devfreq); >>> + if (!devfreq->scaling_min_freq) { >>> + mutex_unlock(&devfreq->lock); >>> + return -EINVAL; >>> + } >>> + >>> + devfreq->scaling_max_freq = find_available_max_freq(devfreq); >>> + if (!devfreq->max_freq) { >> >> 1. s/max_freq/scaling/max_freq/ ?? > > My mistake. The scaling_max_freq is right. I'll fix it. > >> >> 2. what if thermal is not active or has never triggered any event and >> the user has never stated max/min? (making scaling_*_freq zero) > > > The devfreq-cooling.c of tmu uses the OPP interface > and then OPP interface affect the scaling_min/max_freq of devfreq > through dev_pm_opp_disable/enable(). So, even if 'thermal is not active > or has never triggered any event', devfreq will use the OPP interface > as a mandatory. > > In result, I think that devfreq should maintain the correct frequency > of scaling_min/max_freq indicating the 'limit minimum/maximum frequency > requested by OPP interface' instead of zero. > > So, I'll change the description of scaling_min/max_freq as following: > (by devfreq-cooling -> by OPP interface) > On v4: > + * @scaling_min_freq: Limit minimum frequency requested by devfreq-cooling > + * @scaling_max_freq: Limit maximum frequency requested by devfreq-cooling > > On v5: > + * @scaling_min_freq: Limit minimum frequency requested by OPP interface > + * @scaling_max_freq: Limit maximum frequency requested by OPP interface > > > And, this patch showed the wrong value of min/max_freq_show() by my mistake. > I showed the 'min/max_freq' directly through min/max_freq_show() > without comparing with scaling_min/max_freq. So, I'll fix this issue as following: > --------------- > On v5: > static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr, > char *buf) > { > - return sprintf(buf, "%lu\n", to_devfreq(dev)->min_freq); > + struct devfreq *df = to_devfreq(dev); > + > + return sprintf(buf, "%lu\n", MAX(df->scaling_min_freq, df->min_freq)); > } > > static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr, > @@ -1161,7 +1183,9 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr, > static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr, > char *buf) > { > - return sprintf(buf, "%lu\n", to_devfreq(dev)->max_freq); > + struct devfreq *df = to_devfreq(dev); > + > + return sprintf(buf, "%lu\n", MIN(df->scaling_max_freq, df->max_freq)); > ---------------
If you agree my opinion, I'll send v5 patchset right now because if patch3 gets the review, everything is done without patch8. As I replied, I'll drop the patch8 from this patchset.
> > >> >>> + mutex_unlock(&devfreq->lock); >>> + return -EINVAL; >>> + } >>> + >>> ret = update_devfreq(devfreq); >>> mutex_unlock(&devfreq->lock); >>> >> >> >> > >
-- Best Regards, Chanwoo Choi Samsung Electronics
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