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802.11 power mode question

Aviram_Sobol asked
Medium Priority
Last Modified: 2013-12-09
Hi all,
Every body can explain me or redirect for information about power mode behavior?
Specifically, what happens between the NIC and Access Point(AP) when I change the power mode to Ndis802_11PowerModeMAX_PSP.

Really, I am want to notify AP that the NIC is sleeping, so the AP will not send nothig to NIC before it notified that NIC is wake. But I need that NIC is not sleeping this time.

Also, any information about which hardware independent "commands" I can ask the NIC to do that is not NDIS requests is interesting also.
Watch Question


"Ndis802_11PowerModeMAX_PSP specifies the maximum power saving for the 802.11 NIC radio. OID_802_11_POWER_MODE requests that the miniport driver set the power mode of the 802.11 NIC to this value."

Don't understand the question. Could you be a bit more precise?


Thanks, it is not what I need yet, but I will try to explain myself again.
I try to find an information about behavior between STAtion to Access Point.
After you assign Ndis802_11PowerModeMAX_PSP to NIC, what happen after such assignation?
The STA notify AP immidiatelly after assignation about this mode and from this point AP send packets to STA only on demand?
Or the NIC go sleep in some period and notify AP each time about going to sleep?
Ok. Here is a link you may find of interest. It refers to an 802.11g rt2570 USB driver source code:


After reading through the code I found a possible answer for your question. In the PeerBeacon function (executed when a beacon is received from peer) it looks like it performs a number of steps to act when the Infrastructure mode is on and then PowerMode flag is set to PWR_SAVE. This is what they do:

1. AP has backlogged unicast-to-me frame, stay AWAKE, send PSPOLL
2. AP has backlogged broadcast/multicast frame and we want those frames, stay AWAKE
3. we have outgoing frames in TxRing or PrioRing, better stay AWAKE
4. Psm change to PWR_SAVE, but AP not been informed yet, we better stay AWAKE
5. otherwise, put PHY back to sleep to save battery.

It seems to keep connected to the AP until all outstanding frames has been sent out and the AP is informed that we go to sleep. Then it turns the power down to save battery.

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Thanks, opanza.

Moderators\Administrators, please don't close this topic yet, I will back later to this question. (This time I haven't time to continue deal with it)
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