[Nexus 6  Original Android Development] okgnew:
I tried it again: with stock kernel my WiFi works fine.

With your kernel v.15 my WiFi also works fine.

With your kernel v.17 WiFi does not connect to any network. This time I got logs for you (attached).

I see the below messages in the log:

02-22 16:58:51.216 D/WifiService(850): Client connection lost with reason: 4

02-22 16:59:48.416 D/WifiService(850): acquireWifiLockLocked: WifiLock{NlpWifiLock type=2 binder=android.os.BinderProxy@2b40f9af}

02-22 16:59:48.640 D/WifiService(850): releaseWifiLockLocked: WifiLock{NlpWifiLock type=2 binder=android.os.BinderProxy@2b40f9af}

02-22 17:00:14.212 D/MccTable(1388): WIFI_COUNTRY_CODE set to

02-22 17:00:14.213 I/WifiService(850): WifiService trying to set country code to with persist set to true

02-22 17:00:17.709 D/MccTable(1388): WIFI_COUNTRY_CODE set to gb

02-22 17:00:17.710 I/WifiService(850): WifiService trying to set country code to gb with persist set to true

02-22 17:00:49.877 D/WifiService(850): acquireWifiLockLocked: WifiLock{ES Wifi Lock type=3 binder=android.os.BinderProxy@31b932f2}

02-22 17:00:49.986 D/WifiService(850): releaseWifiLockLocked: WifiLock{ES Wifi Lock type=3 binder=android.os.BinderProxy@31b932f2}

02-22 17:00:50.502 D/WifiService(850): acquireWifiLockLocked: WifiLock{NlpWifiLock type=2 binder=android.os.BinderProxy@46a486d}

02-22 17:02:04.967 W/FORESEE_DEBUG(7107): Could not respond to network event due to class com.google.inject.ConfigurationException

02-22 17:02:04.970 I/AviaryCdsReceiver(7175): ACTION: android.net.wifi.STATE_CHANGE

02-22 17:02:04.978 W/FORESEE_DEBUG(9294): Could not respond to network event due to class com.google.inject.ConfigurationException

02-22 17:02:04.987 W/FORESEE_DEBUG(7107): Could not respond to network event due to class com.google.inject.ConfigurationException

02-22 17:02:04.990 I/AviaryCdsReceiver(7175): ACTION: android.net.wifi.STATE_CHANGE

02-22 17:02:06.253 E/Crashlytics(1500):	... 23 more

02-22 17:02:09.370 I/wpa_supplicant(1068): wlan0: CTRL-EVENT-SCAN-STARTED

02-22 17:02:09.389 W/FORESEE_DEBUG(9294): Could not respond to network event due to class com.google.inject.ConfigurationException

02-22 17:02:09.402 W/FORESEE_DEBUG(7107): Could not respond to network event due to class com.google.inject.ConfigurationException

02-22 17:02:09.406 I/AviaryCdsReceiver(7175): ACTION: android.net.wifi.STATE_CHANGE

02-22 17:02:09.802 D/HeadsetStateMachine(2554): Disconnected process message: 10, size: 0

02-22 17:02:11.970 E/WifiStateMachine(850): WifiStateMachine shouldSwitchNetwork txSuccessRate=0.00 rxSuccessRate=0.00 delta 1000 -> 1000

02-22 17:02:11.978 E/WifiStateMachine(850): CMD_AUTO_CONNECT sup state ScanState my state DisconnectedState nid=26 roam=3

02-22 17:02:11.979 E/WifiConfigStore(850): saveWifiConfigBSSID Setting BSSID for "Marriott Gatwick"NONE to any

02-22 17:02:11.981 E/WifiStateMachine(850): CMD_AUTO_CONNECT will save config -> "Marriott Gatwick" nid=26

02-22 17:02:11.983 E/WifiConfigStore(850): will read network variables netId=26

02-22 17:02:11.990 E/WifiStateMachine(850): CMD_AUTO_CONNECT did save config -> nid=26

02-22 17:02:11.990 E/WifiConfigStore(850): will read network variables netId=26

02-22 17:02:11.997 I/wpa_supplicant(1068): wlan0: Trying to associate with SSID 'Marriott Gatwick'

02-22 17:02:11.998 D/WifiMonitor(850): didn't find BSSID Trying to associate with SSID 'Marriott Gatwick'

02-22 17:02:12.004 E/WifiConfigStore(850): setLastSelectedConfiguration -1

02-22 17:02:12.032 W/FORESEE_DEBUG(9294): Could not respond to network event due to class com.google.inject.ConfigurationException

02-22 17:02:12.043 W/FORESEE_DEBUG(7107): Could not respond to network event due to class com.google.inject.ConfigurationException

02-22 17:02:12.047 I/AviaryCdsReceiver(7175): ACTION: android.net.wifi.STATE_CHANGE

02-22 17:02:12.055 W/FORESEE_DEBUG(9294): Could not respond to network event due to class com.google.inject.ConfigurationException

02-22 17:02:12.063 W/FORESEE_DEBUG(7107): Could not respond to network event due to class com.google.inject.ConfigurationException

02-22 17:02:12.066 I/AviaryCdsReceiver(7175): ACTION: android.net.wifi.STATE_CHANGE

02-22 17:02:15.744 E/NetlinkEvent(340): NetlinkEvent::FindParam(): Parameter 'INTERFACE' not found

02-22 17:02:15.744 E/NetlinkEvent(340): NetlinkEvent::FindParam(): Parameter 'TIME_NS' not found

02-22 17:02:15.747 E/NetdConnector(850): Error handling '613 IfaceClass idle (null)': java.lang.NumberFormatException: Invalid int: "(null)"

02-22 17:02:19.842 D/HeadsetStateMachine(2554): Disconnected process message: 10, size: 0

02-22 17:02:19.857 D/HeadsetStateMachine(2554): Disconnected process message: 10, size: 0

02-22 17:02:22.004 I/wpa_supplicant(1068): wlan0: Authentication with 00:00:00:00:00:00 timed out.

02-22 17:02:22.006 I/wpa_supplicant(1068): wlan0: CTRL-EVENT-DISCONNECTED bssid=00:00:00:00:00:00 reason=3 locally_generated=1

02-22 17:02:22.007 I/wpa_supplicant(1068): wlan0: CTRL-EVENT-ASSOC-REJECT status_code=1

02-22 17:02:22.032 W/FORESEE_DEBUG(9294): Could not respond to network event due to class com.google.inject.ConfigurationException

02-22 17:02:22.048 W/FORESEE_DEBUG(7107): Could not respond to network event due to class com.google.inject.ConfigurationException

02-22 17:02:22.050 I/AviaryCdsReceiver(7175): ACTION: android.net.wifi.STATE_CHANGE

02-22 17:02:22.058 W/FORESEE_DEBUG(9294): Could not respond to network event due to class com.google.inject.ConfigurationException

02-22 17:02:22.066 W/FORESEE_DEBUG(7107): Could not respond to network event due to class com.google.inject.ConfigurationException

02-22 17:02:22.069 I/AviaryCdsReceiver(7175): ACTION: android.net.wifi.STATE_CHANGE