More observations about the issue. Below is screenshot of typical broken connection session. Notice that Windows Network Manager reports Connected state [1] (that's incorrect and Connection time and Bytes send/received are also weird [3]) while Access Connections reports Not connected [2]. Pressing the 'Disconnect' button does not have any effect, it still remains in the (incorrect) Connected state in Windows Network Manager. Any other attemp to connect via Access Connections fails.

Steps I've tried:

1. Disable/Enable WWAN via Fn+F5 -> no effect

2. Restart 'WWAN AutoConfig' windows service -> no effect

3. Restart 'Mobile Broadband Service' windows service -> no effect

4. Disable and Enable 'F5521gw Mobile Broadband Driver' in Device Manager -> success, the WWAN connection was immediately reconnected

That confirms that the driver is buggy. There are no related messages in Event Log so there is no way to diagnose the issue :smileyfrustrated: Restarting the driver is not a solution since it requires Administrator privileges.

Access Connections version is 5.95 but the behavior was exactly the same with older versions as well. And yes, I use Lenovo factory preload. I also run full chkdsk /f and sfc /scannow to make sure there are no file system errors.

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wrote:

 

Are your pc purely staged with the Lenovo preload?

 

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Note that Puppy is not a pure factory pre-load .

Hi Puggy

Please contact me

We have made a breakthrough although I must say it is not driver related, but a specific component, which I would like to know if you are also using.

Please do have a nice day

BR

Lasse

Moderator note; e-mail address removed to stop the spambots getting it

One more detail that has to be clarified. Lasse has been experiencing different issue than me.

My issue is that I can manually connect/disconnect hundred times (either via Access Connections or Windows Network Manager) without a problem. But in case of unexpected disconnection (due a poor signal, lost signal in train etc.) it has the behavior described before that prevents further reconnection. There are similar reports in local czech notebook forums for other x20 models (T420, W520).

Similar problem in X tablet forum http://forums.lenovo.com/t5/X-Series-Tablet-ThinkPad-Laptops/Ericsson-F5521gw-WWAN-disconnects-intermittently-and-cannot/m-p/618391

Since there are people who does not experience these problems, could you please check version of  Wwansvc.dll in your windows system32 folder ? I have 8.1.2.0 (14 Jul 2009) now but there is MS hotfix http://support.microsoft.com/kb/2615592 (fixing different issue) with updated one. Just wondering whether you have the updated one. Thanks.

There is list of other WWAN related system dlls to check (Windows 7 SP1 Prof x64)

Directory of c:\Windows\System32

14.07.2009  03:41           196 608 Wwanadvui.dll
14.07.2009  03:41           368 640 WWanAPI.dll
14.07.2009  03:41            49 664 wwancfg.dll
21.11.2010  05:24           222 720 wwanconn.dll
14.07.2009  03:41            73 728 WWanHC.dll
14.07.2009  03:41            15 872 wwaninst.dll
14.07.2009  03:41           693 248 wwanmm.dll
14.07.2009  03:41            46 592 Wwanpref.dll
21.11.2010  05:24            48 640 wwanprotdim.dll
14.07.2009  03:41           229 888 wwansvc.dll
14.07.2009  03:41            36 352 wwapi.dll
              11 File(s)      1 981 952 bytes

Puppy,

here you are:

 Содержимое папки C:\Windows\System32

14.07.2009  05:41           196 608 Wwanadvui.dll
14.07.2009  05:41           368 640 WWanAPI.dll
14.07.2009  05:41            49 664 wwancfg.dll
20.11.2010  17:27           222 720 wwanconn.dll
14.07.2009  05:41            73 728 WWanHC.dll
14.07.2009  05:41            15 872 wwaninst.dll
14.07.2009  05:41           693 248 wwanmm.dll
14.07.2009  05:41            46 592 Wwanpref.dll
20.11.2010  17:27            48 640 wwanprotdim.dll
14.07.2009  05:41           229 888 wwansvc.dll
14.07.2009  05:41            36 352 wwapi.dll
              11 файлов      1 981 952 байт

 wwansvc.dll file version is the same, 8.1.2.0. Windows Pro is up to date.

I've made my last attempt to resolve the issue. I enabled network traces for mbn (WWAN module) and ndis scenarios and waited for the unexpected disconnection. As usually, I couldn't not reconnect again. I have full traces of the corrupted connection session, including errorcodes from the WWAN driver (which I still guess is the victim) and NDIS communication.

The question is where to send these ETL files (for Microsoft Network Monitor 3.4 on Windows 7/2008) to diagnose them ? Ericsson no longer accepts any bug reports because these modules are unsupported since December 2011. Does Lenovo continues to develop the driver now ?

Typical errors are:

  Frame: Number = 381, Captured Frame Length = 121, MediaType = NetEvent
+ NetEvent:
- MicrosoftWindowsWWANSVCEVENTS: WWAN Service event: Connect request failed
  - EV_WWAN_CONNECT_FAILED: WWAN Service event: Connect request failed
     InterfaceGuid: {1F09BC65-7665-4E60-A83B-949270D18857}
     EventCode: 15 (0xF)
   - ErrorCode: ERROR_SUCCESS
      WinErrorValue: 0x00000000 - ERROR_SUCCESS - The operation completed successfully.
   - NetworkErrorCode: 0xC0040003 - Unknown Value
    - ErrorValue: 0xC0040003 - Unknown Value
       Code:      (................0000000000000011) 0xC0040003 - Unknown Value
       Facility:  (.....00000000100................) ITF
       X:         (....0...........................) Reserved
       N:         (...0............................) Not NTSTATUS
       C:         (..0.............................) Microsoft-defined
       R:         (.1..............................) Reserved
       S:         (1...............................) Failure
     RequestID: 0 (0x0)

  Frame: Number = 337, Captured Frame Length = 121, MediaType = NetEvent
+ NetEvent:
- MicrosoftWindowsWWANSVCEVENTS: WWAN Service event: Disconnect request failed
  - EV_WWAN_DISCONNECT_FAILED: WWAN Service event: Disconnect request failed
     InterfaceGuid: {1F09BC65-7665-4E60-A83B-949270D18857}
     EventCode: 17 (0x11)
   - ErrorCode: ERROR_SUCCESS
      WinErrorValue: 0x00000000 - ERROR_SUCCESS - The operation completed successfully.
   - NetworkErrorCode: 0xC0040011 - Unknown Value
    - ErrorValue: 0xC0040011 - Unknown Value
       Code:      (................0000000000010001) 0xC0040011 - Unknown Value
       Facility:  (.....00000000100................) ITF
       X:         (....0...........................) Reserved
       N:         (...0............................) Not NTSTATUS
       C:         (..0.............................) Microsoft-defined
       R:         (.1..............................) Reserved
       S:         (1...............................) Failure
     RequestID: 0 (0x0)

Developers of the Ericsson WWAN driver should have known what the error code means. Restarting the driver (via devcon Windows DDK utility) seems to help but it is not a solution since it requires administrator privileges.

It seems as I have finally found a workaround. Studying the network traces I found that Access Connections are subscribed to WWAN module events (connect, disconnect). After update to AC version 5.97, it is no longer subscribed if the connection is not started by Access Connections but Windows native network manager.

The workaround is that I use Windows native network manager to start WWAN connection instead of Access Connections. Version 5.97 of AC is no longer being notified about the connection started from Windows native network manager (AC reports Not Connected, fortunately the status icon still reports signal level, connection time etc.). When the connection drops, I can finally reconnect again by Windows native network manager.

Access Connections probably does not process the unexpected disconnection event (if subscribed to receive WWAN events) properly and leaves the WWAN driver in corrupted or stuck (waiting for message response) state.