Re: [PATCH v2 4/4] ath10k: Enable sta idle power save

[Kalle Valo <kvalo@codeaurora.org>]

govinds@codeaurora.org writes:

> On 2018-04-18 18:46, Kalle Valo wrote:
>> (fixing top posting)
>>
>> govinds@codeaurora.org writes:
>>
>>> On 2018-04-18 12:36, Sebastian Gottschall wrote:
>>>> from my point of view powersave should be optional and not forced.
>>>>
>>>> consider :
>>>> iw dev <devname> set power_save on/off
>>>>
>>>> so there is already a config option made for that purpose,
>>>
>>> Thanks Sebastian for your review. Agree this should not be forced with
>>> in driver.
>>>
>>> I will check if i can set the idle ps at the end of
>>> ath10k_mac_vif_setup_ps by checking arvif->ps.
>>> I will update the patch accordingly.
>>
>> So what power save is this exactly? I assumed it's some bus level power
>> save (turning of clocks etc) but is it actually 802.11 power save?
>
> Yes this is WIFI chip set level power-save(based on idleness) and not
> related to protocol power save. FW will turn off/scale down the
> resources(clock/rails) based on opportunity(when ever idle mode is
> detected). This power save is mostly done in disconnected state. I am
> not really sure when framework/user-space triggers power-save
> config(iw dev <devname> set power_save on/off). Then doing this from
> user-space will be unnecessarily toggling this config or may not be
> setting at disconnected state.

I think that 'set power_save' commands affects struct
ieee80211_bss_conf::ps parameter and I don't think it should be used in
this case. We already have ath10k_config_ps() for 802.11 level of power
saving.

Arend again proposed runtime-pm with which I'm not very familiar. But
why would we want to disable this? Doesn't it make sense to have this
feature always enabled to save power? wcn3990 is a chip for a mobile
device anyway.

-- 
Kalle Valo