Messages in this thread Patch in this message | | | Date | Wed, 18 Oct 2017 10:31:02 +0900 | From | Chanwoo Choi <> | Subject | Re: [PATCH v4 3/8] PM / devfreq: Use the available min/max frequency |
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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)); ---------------
>> + mutex_unlock(&devfreq->lock); >> + return -EINVAL; >> + } >> + >> ret = update_devfreq(devfreq); >> mutex_unlock(&devfreq->lock); >> > > >
-- Best Regards, Chanwoo Choi Samsung Electronics
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