From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lukasz Luba Subject: Re: [PATCH 2/6] devfreq: refactor set_target frequency function Date: Thu, 22 Nov 2018 11:40:09 +0100 Message-ID: <9eef3348-e86f-1113-3691-39ba3a620fb8@partner.samsung.com> References: <1542823301-23563-1-git-send-email-l.luba@partner.samsung.com> <1542823301-23563-3-git-send-email-l.luba@partner.samsung.com> <5BF619EE.8090006@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <5BF619EE.8090006@samsung.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Chanwoo Choi , linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, devicetree@vger.kernel.org Cc: tjakobi@math.uni-bielefeld.de, myungjoo.ham@samsung.com, kyungmin.park@samsung.com, rjw@rjwysocki.net, len.brown@intel.com, pavel@ucw.cz, gregkh@linuxfoundation.org, keescook@chromium.org, anton@enomsg.org, ccross@android.com, tony.luck@intel.com, robh+dt@kernel.org, mark.rutland@arm.com, kgene@kernel.org, krzk@kernel.org, m.szyprowski@samsung.com, b.zolnierkie@samsung.com List-Id: linux-pm@vger.kernel.org Hi Chanwoo Choi On 11/22/18 3:52 AM, Chanwoo Choi wrote: > On 2018년 11월 22일 03:01, Lukasz Luba wrote: >> The refactoring is needed for the new client in devfreq: suspend. >> To avoid code duplication, move it to the new local function >> devfreq_set_target. >> >> The patch draws on Tobias Jakobi's work posted ~2 years ago, who tried to >> solve issue with devfreq device's frequency during suspend/resume. >> During the discussion on LKML some corner cases and comments appeared >> related to the design. This patch address them keeping in mind suggestions >> from Chanwoo Choi. > > As I commented on patch1, please remove it. OK > >> >> Suggested-by: Tobias Jakobi >> Suggested-by: Chanwoo Choi >> Signed-off-by: Lukasz Luba >> --- >> drivers/devfreq/devfreq.c | 62 ++++++++++++++++++++++++++++------------------- >> 1 file changed, 37 insertions(+), 25 deletions(-) >> >> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c >> index e20e7e4..cf9c643 100644 >> --- a/drivers/devfreq/devfreq.c >> +++ b/drivers/devfreq/devfreq.c >> @@ -285,6 +285,42 @@ static int devfreq_notify_transition(struct devfreq *devfreq, >> return 0; >> } >> >> +static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq, >> + unsigned long *prev_freq, u32 flags) > > Please remove the unused space in front of 'unsigned long *prev_freq'. > Use tab only for indentation. OK > >> +{ >> + struct devfreq_freqs freqs; >> + unsigned long cur_freq; >> + int err = 0; >> + >> + if (devfreq->profile->get_cur_freq) >> + devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq); >> + else >> + cur_freq = devfreq->previous_freq; >> + >> + freqs.old = cur_freq; >> + freqs.new = new_freq; >> + devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE); >> + >> + err = devfreq->profile->target(devfreq->dev.parent, &new_freq, flags); >> + if (err) { >> + freqs.new = cur_freq; >> + devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE); >> + return err; >> + } >> + >> + freqs.new = new_freq; >> + devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE); >> + >> + if (devfreq_update_status(devfreq, new_freq)) >> + dev_err(&devfreq->dev, >> + "Couldn't update frequency transition information.\n"); >> + >> + devfreq->previous_freq = new_freq; >> + *prev_freq = cur_freq; >> + >> + return err; >> +} >> + >> /* Load monitoring helper functions for governors use */ >> >> /** >> @@ -296,7 +332,6 @@ static int devfreq_notify_transition(struct devfreq *devfreq, >> */ >> int update_devfreq(struct devfreq *devfreq) >> { >> - struct devfreq_freqs freqs; >> unsigned long freq, cur_freq, min_freq, max_freq; > > > cur_freq is not used after modification. Remove it. > >> int err = 0; >> u32 flags = 0; >> @@ -333,31 +368,8 @@ int update_devfreq(struct devfreq *devfreq) >> flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */ >> } >> >> - if (devfreq->profile->get_cur_freq) >> - devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq); >> - else >> - cur_freq = devfreq->previous_freq; >> - >> - freqs.old = cur_freq; >> - freqs.new = freq; >> - devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE); >> + return devfreq_set_target(devfreq, freq, &cur_freq, flags); > > You get the 'cur_freq' from devfreq_set_taget() for devfreq_suspend_device() on patch3. > But, update_devfreq() and devfreq_resume_device() don't use the 'cur_freq' value > from devfreq_set_target(). > > Instead, getting 'cur_freq' for 'devfreq->resume_freq' in the devfreq_set_target(). > Please remove the 'cur_freq' parameter from devfreq_set_target. I can remove the 3rd parameter from devfreq_set_target(), but it implies that patch 1 and 3 cannot be merged. The function devfreq_set_target will use 'devfreq->resume_freq' so it must be in devfreq struct. So, in v2 version there will be still 6 patches, with the 1st patch defining needed fields in devfreq struct. Do you agree for that? > >> >> - err = devfreq->profile->target(devfreq->dev.parent, &freq, flags); >> - if (err) { >> - freqs.new = cur_freq; >> - devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE); >> - return err; >> - } >> - >> - freqs.new = freq; >> - devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE); >> - >> - if (devfreq_update_status(devfreq, freq)) >> - dev_err(&devfreq->dev, >> - "Couldn't update frequency transition information.\n"); >> - >> - devfreq->previous_freq = freq; >> - return err; >> } >> EXPORT_SYMBOL(update_devfreq); >> >> > > Regards, Lukasz Luba