Why does Wake On Wireless (WoW) wake Android only once?

1. Android is connected to a WiFi network 2. The device sleeps: [ 7917.653293] PM: Syncing filesystems ... done. [ 7917.660344] Freezing user space processes ... (elapsed 0.02 seconds) done. [ 7917.681675] Freezing remaining freezable tasks ... (elapsed 0.00 seconds) done. [ 7917.683022] Suspending console(s) (use no_console_suspend to debug) ... [ 7917.701339] Suspend for wow mode ... [ 7917.855690] Wow enabled. Not allow to send tx data [ 7917.957487] Setup WoW suc[ 7917.653293] PM: Syncing filesystems ... done. [ 7917.660344] Freezing user space processes ... (elapsed 0.02 seconds) done. [ 7917.681675] Freezing remaining freezable tasks ... (elapsed 0.00 seconds) done. [ 7917.683022] Suspending console(s) (use no_console_suspend to debug) ... [ 7917.701339] Suspend for wow mode ... [ 7917.855690] Wow enabled. Not allow to send tx data [ 7917.957487] Setup WoW successfully ...cessfully ... 3. I ping it from remote: [ 7917.958113] ar6000_pm_resume: enter status 3 [ 7917.959225] android_ar6k_check_wow_status: WoW resume from irq thread status 0 [ 7917.959377] Resume WoW successfully [ 7917.960300] WoW does not invoked. skip resumeES209RA Audio Jack Driver : es209ra_audio_jack_resume START ... [ 7918.144031] Restarting tasks ... done. 4. The device wakes up (without turning the screen on) and responds on the network. 5. But then (after about 2-3 seconds) it suspends again: [ 7918.240298] suspend: exit suspend, ret = 0 (2012-01-15 11:48:35.684507919 UTC) [ 7918.967615] save exit: isCheckpointed 1 [ 7918.972936] PM: Syncing filesystems ... done. 6. Now it does _not_ resume on wireless. When I press some hardware button, the phone resumes, sleeps and I have one more opportunity to resume it from WiFi. But only once. Why does it fail to resume from WiFi every time?