From: Chanwoo Choi <cw00.choi@samsung.com>
To: Lukasz Luba <l.luba@partner.samsung.com>,
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
Subject: Re: [PATCH 2/6] devfreq: refactor set_target frequency function
Date: Thu, 22 Nov 2018 11:52:30 +0900 [thread overview]
Message-ID: <5BF619EE.8090006@samsung.com> (raw)
In-Reply-To: <1542823301-23563-3-git-send-email-l.luba@partner.samsung.com>
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.
>
> Suggested-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
> Suggested-by: Chanwoo Choi <cw00.choi@samsung.com>
> Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>
> ---
> 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.
> +{
> + 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.
>
> - 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);
>
>
--
Best Regards,
Chanwoo Choi
Samsung Electronics
next prev parent reply other threads:[~2018-11-22 2:52 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20181121180156eucas1p225af7f4341a039264ff26f2a9ad9bb12@eucas1p2.samsung.com>
2018-11-21 18:01 ` [PATCH 0/6] devfreq: handle suspend/resume Lukasz Luba
[not found] ` <CGME20181121180201eucas1p1f1f96941c3d16a96722e65d5c21bfe80@eucas1p1.samsung.com>
2018-11-21 18:01 ` [PATCH 1/6] devfreq: add basic fileds supporting suspend functionality Lukasz Luba
2018-11-22 2:37 ` Chanwoo Choi
[not found] ` <CGME20181121180202eucas1p27d3aa58411abeae03181c38b91fc67de@eucas1p2.samsung.com>
2018-11-21 18:01 ` [PATCH 2/6] devfreq: refactor set_target frequency function Lukasz Luba
2018-11-22 2:52 ` Chanwoo Choi [this message]
2018-11-22 2:54 ` Chanwoo Choi
2018-11-22 10:40 ` Lukasz Luba
2018-11-22 23:45 ` Chanwoo Choi
2018-11-23 9:58 ` Lukasz Luba
[not found] ` <CGME20181121180204eucas1p1c5891d498aa59c0e10dd3ba4727a4382@eucas1p1.samsung.com>
2018-11-21 18:01 ` [PATCH 3/6] devfreq: add support for suspend/resume of a devfreq device Lukasz Luba
2018-11-22 2:58 ` Chanwoo Choi
2018-11-22 11:00 ` Lukasz Luba
2018-11-22 23:54 ` Chanwoo Choi
2018-11-23 10:01 ` Lukasz Luba
2018-11-26 0:19 ` Chanwoo Choi
2018-12-03 14:05 ` Lukasz Luba
[not found] ` <CGME20181121180205eucas1p1dc52369476400cd07058d232bd8dbcd7@eucas1p1.samsung.com>
2018-11-21 18:01 ` [PATCH 4/6] devfreq: add devfreq_suspend/resume() functions Lukasz Luba
2018-11-22 3:07 ` Chanwoo Choi
2018-11-22 11:02 ` Lukasz Luba
[not found] ` <CGME20181121180206eucas1p265865226e3938a28e842e8367233dc2e@eucas1p2.samsung.com>
2018-11-21 18:01 ` [PATCH 5/6] drivers: power: suspend: call devfreq suspend/resume Lukasz Luba
2018-11-22 3:08 ` Chanwoo Choi
[not found] ` <CGME20181121180208eucas1p11482a783ab1b1bceb8c9f6a1f50682c3@eucas1p1.samsung.com>
2018-11-21 18:01 ` [PATCH 6/6] arm: dts: exynos4: set opp-suspend for DMC and leftbus Lukasz Luba
2018-11-22 3:09 ` Chanwoo Choi
2018-11-22 11:04 ` Lukasz Luba
2018-11-22 17:24 ` [PATCH 0/6] devfreq: handle suspend/resume Tobias Jakobi
2018-11-22 17:44 ` Lukasz Luba
[not found] ` <CGME20181121180201eucas1p1f1f96941c3d16a96722e65d5c21bfe80@epcms1p8>
2018-11-26 8:14 ` [PATCH 1/6] devfreq: add basic fileds supporting suspend functionality MyungJoo Ham
2018-12-03 14:03 ` Lukasz Luba
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