On Thu, 2021-12-16 at 13:01 +0000, Ajay.Kathat@microchip.com wrote:

On 16/12/21 11:07, David Mosberger-Tang wrote:

quoted

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On Wed, 2021-12-15 at 13:01 +0000, Ajay.Kathat@microchip.com wrote:

quoted

On 13/12/21 02:50, David Mosberger-Tang wrote:

quoted

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Unfortunately, this patch doesn't seem to be sufficient.  From what I
can tell, if power-save mode is turned on before a station is
associated with an access-point, there is no actual power savings.  If
I issue the command after the station is associated, it works perfectly
fine.

Ajay, does this make sense to you?

  <snip>
Power-save mode is allowed to be enabled irrespective of station
association state. Before association, the power consumption should be
less with PSM enabled compared to PSM disabled. The WLAN automatic power
save delivery gets enabled after the association with AP.

To check the power measurement before association,  test without
wpa_supplicant.


Steps:
- load the module
- ifconfig wlan0 up
- iw dev wlan0 set power_save off (check the pwr measurement after PS
mode disabled)
- iw dev wlan0 set power_save on (check the pwr measurement after PS
mode enable)

It appears wpa_supplicant consistently renders PSM ineffective:

                                (current draw, 1 min avg):
------------------------------  --------------------------
- base case (no module loaded): 16.8 mA
- module loaded & PSM on      : 16.8 mA
- wpa_supplicant started      : 19.6 mA
- PSM on                      : 19.6 mA (no change)
- PSM off                     : 19.6 mA (no change)
- PSM on                      : 15.4 mA

 
From the above data, it looks like there is no difference with or without PSM
in your setup. I am not sure if the values are captured correctly. Did you use
power measurement ports in WILC extension for the current measurements.

Oh, no, not at all!  There is a nice power savings when PSM actually takes hold.
 Current drops from 19.6mA to 15.4mA as shown by the last two lines.

This is average current draw at 120V for the entire board, as my board is not
set up to measure chip current draw alone.

quoted

What's strange is when I try this sequence a couple of times in a row,
the device gets into a state where after starting wpa_supplicant, no
amount of PSM on/off commands will get it to enter power-savings mode
any more.  When in that state, only removing wilc1000-spi.ko and adding
it back gets it out of that state.  A power-cycle does not.  Very
confusing.

Btw, I did a quick test to verify current measurement with PS mode off/on and observed numbers like below

Tested by making the interface up(ifconfig wlan0 up) then issued 'iw' command to enable/disable PS mode. 

                              (current draw)
------------------------------------------------------
- PSM off                    : 75.5 mA
- PSM on                     : 1.28 mA


I have verified for SPI module with the setup mentioned in link[1] and used power debugger[2]

1. https://ww1.microchip.com/downloads/en/Appnotes/ATWILC1000-Power-Measurement-for-Wi-Fi-Link-Controller-00002797A.pdf
2. https://www.microchip.com/en-us/development-tool/ATPOWERDEBUGGER

Sure, I assume your measurements are at 3.3V for the chip alone.

But the question is: what happens once you start wpa_supplicant?

  --david