[PATCH v1 & v6 1/2] PM/devfreq: add suspend frequency support
hl at rock-chips.com
Wed Nov 23 23:34:39 PST 2016
Hi Chanwoo Choi,
I think the dev_pm_opp_get_suspend_opp() have implement most of
the funtion, all we need is just define the node in dts, like following:
so i think my way semm more simple.
On 2016年11月24日 15:10, Chanwoo Choi wrote:
> + Tobias Jakobi,
> Hi Lin,
> We need to discuss how to support the suspend-opp of devfreq device.
> Now, there are two patch thread for suspend-opp of devfreq.
> The Lin's approach modify the devfreq_suspend_device() to support suspend-opp.
> The Tobias's approach add new devfreq_suspend() and then call it on dpm_suspend()
> when entering the suspend state.
>  [RFC 0/4] PM / devfreq: draft for OPP suspend impl
> - https://patchwork.kernel.org/patch/9443323/
> - https://patchwork.kernel.org/patch/9443325/
> - https://patchwork.kernel.org/patch/9443329/
> - https://patchwork.kernel.org/patch/9443331/
> I think we need to discuss it together.
> Chanwoo Choi
> On 2016년 11월 24일 15:45, hl wrote:
>> Hi MyungJoo Ham,
>> On 2016年11月24日 14:14, MyungJoo Ham wrote:
>>> On Thu, Nov 24, 2016 at 11:18 AM, hl <hl at rock-chips.com> wrote:
>>>> Hi MyungJoo Ham,
>>>>> We still need to sync the all status even i call target() in
>>>>> directly, so still need update_devfreq() other setp except
>>>>> devfreq->governor->get_target_freq(devfreq, &freq);
>>>> And i think it better to be governor behaviors, for userspace they may not
>>>> want to change
>>>> the suspend frequency like other governor, the frequency should decide by
>>>> the user, if they
>>>> want this function, they should like other governor to rigister a
>>>> What do you think about my rev6 patch?
>>> If I understand the intention correctly, this is for the stability of
>>> the device due to the behavior or bootloader/SoC-initializer, which
>>> has nothing to do with governors.
>>> Even if users are using userspace, as long as they set the custom
>>> frequencies lower than the default, they have the possibility of
>>> being unstable as ondemand is going to have.
>>> To reuse the update_devfreq() code, you may do something like:
>>> static int _update_freq(struct devfreq *devfreq, bool is_suspending)
>>> /* original contents of update_freq with if statement with is_suspending wrapping get_target_freq */
>>> int update_freq(struct devfreq *devfreq)
>>> return _update_freq(devfreq, false);
>>> There should be other good non-invasive methods that are not governoe-specific as well.
>> Thanks for your suggestion, i will update the new version soon.
>>> Linux-rockchip mailing list
>>> Linux-rockchip at lists.infradead.org
>> Lin Huang
More information about the Linux-rockchip