[PATCH 1/2] wifi: mt76: mt7921: Disable powersaving by default

[Mario Limonciello]

On 12/14/2023 06:39, James Prestwood wrote:
> On 12/13/23 11:27, Mario Limonciello wrote:
>> On 12/13/2023 08:45, Ben Greear wrote:
>>> On 12/13/23 5:26 AM, Lorenzo Bianconi wrote:
>>>>> Mario Limonciello <mario.limonciello at amd.com> writes:
>>>>>
>>>>>> Several users have reported awful latency when powersaving is enabled
>>>>>> with certain access point combinations.
>>>>>
>>>>> What APs are these exactly? In the past 802.11 Power Save Mode was
>>>>> challenging due to badly behaving APs. But nowadays with so many 
>>>>> mobile
>>>>> devices in the market I would assume that APs work a lot better. It
>>>>> would be best to investigate the issues in detail and try to fix 
>>>>> them in
>>>>> mt76, assuming the bugs are in mt76 driver or firmware.
>>>>>
>>>>>> It's also reported that the powersaving feature doesn't provide an
>>>>>> ample enough savings to justify being enabled by default with these
>>>>>> issues.
>>>>>
>>>>> Any numbers or how was this concluded?
>>>>>
>>>>>> Introduce a module parameter that would control the power saving
>>>>>> behavior.  Set it to default as disabled. This mirrors what some 
>>>>>> other
>>>>>> WLAN drivers like iwlwifi do.
>>>>>
>>>>> We have already several ways to control 802.11 power save mode:
>>>>>
>>>>> * NL80211_CMD_SET_POWER_SAVE (for example used by 'iw set power_save')
>>>>>
>>>>> * CONFIG_CFG80211_DEFAULT_PS (for kernel level default)
>>>>>
>>>>> * WIPHY_FLAG_PS_ON_BY_DEFAULT (for the driver to control the 
>>>>> default setting)
>>>>>
>>>>> Adding module parameters as a fourth method sounds confusing so not
>>>>> really a fan of this. And the bar is quite high for adding new module
>>>>> parameters anyway.
>>>>
>>>> agree, I think we do not need a new parameter for this, just use the 
>>>> current
>>>> APIs.
>>>
>>> Is there a convenient way for a user to make any of those options 
>>> above stick through
>>> reboots?
>>>
>>> To me, the ability to set system defaults through reboots is a nice 
>>> feature of
>>> module options.
>>>
>>> Thanks,
>>> Ben
>>>
>>
>> Some userspace has the ability to do this.  For example in Network 
>> Manager:
>>
>> https://unix.stackexchange.com/questions/595116/wi-fi-powersaving-in-networkmanager
> 
> And recently added to IWD for this very reason, there are no decent ways 
> to persist between reboots (except when using NM).
> 
> https://git.kernel.org/pub/scm/network/wireless/iwd.git/commit/?id=29edb1626d88bb713db71f7b374d8f24832fd94f
> 
> Thanks,
> 
> James
> 

All,

Just wanted to update you that I looked at this issue again over the 
holidays and it's fixed by upgrading the linux-firmware for the mt7921 
that was submitted in late November.

I get the correct performance and latency without modifying power saving 
now on my Unifi access points.

Thanks,