High battery usage with ath11k on Dell 9310

[Mark Herbert]

Simply disabling wifi  drops 0.8-1 watts from power consumption. 
Comparing almost same model (16 gb RAM vs 32) but based on Intel card 
shows the same difference - Intel based laptop with WiFi connected 
consumes about same as ath11k with Wifi discnnected.

Powertop  newer shows PC states below PC6. Disabling WiFi allows PC8, 
disabling ath11k completely (bios) - PC10.

Wifi enabled

            Pkg(HW)
C2 (pc2)   18,5%    |
C3 (pc3)   14,2%    |
C6 (pc6)   47,5%    |
C7 (pc7)    0,0%    |
C8 (pc8)    0,0%    |
C9 (pc9)    0,0%    |
C10 (pc10)  0,0%    |

Wfi disabled (by networkmanager/nm-applet)


            Pkg(HW)
C2 (pc2)   10,8%    |
C3 (pc3)   18,5%    |
C6 (pc6)    1,1%    |
C7 (pc7)    0,3%    |
C8 (pc8)   28,3%    |
C9 (pc9)    0,0%    |
C10 (pc10)  0,0%    |

Seems that even on no network activity ath11k forces CPU to stay awake 
and eat battery. There are some background transfer happening as I have 
Viber, thunderbird and firefox opened so I bet they do sent some but 
there is no file transfers, media streams etc. Under the same conditions 
(taking this disk from one 9310 to other 9310 - same software, same 
kernel - just wifi's different) - iwlwifi manages to reach PC8-PC10 
being connected.  With ath10k on dell XPS-13 9350 intel also was saving 
battery much better than ath10k, bit there was like 88% of PC10 with 
intel and 65% PC10 and 20% PC8 with ath10k. But it was not such terribly 
bad as with ath11.

There is already kernel bug for this, not creating duplicates

https://bugzilla.kernel.org/show_bug.cgi?id=214543