PowerScheduler synchronization/concurrency bug (1 Viewer)

[seco]

There's seems to be some kind of synchronization problem in TV-Server PowerScheduler when entering to standby.

NullReferenceException can be found from error.log which is caused by _powerManager.AllowStandby() call in PowerScheduler.cs get_DisAllowShutdown() method.

I did testing with SVN 19574 compiled as debug build, tv.log has couple of debug log lines added by me and error.log tells the line number where exception occurs.

The main problem is that Stop() method is called for PowerScheduler plugin just before entering standby, which sets _powerManager to null, but after that (almost at the same time) DisAllowShutdown() method gets called anyway (call is caused by another thread) and error occurs.

Already discussed about the problem @ IRC with Bavarian. I don't know how someone else than me could reproduce this, for me it happens every time when entering to standby (and because of that, automatic wake up doesn't work if there are scheduled recordings or EPG grab, because final wake up time doesn't get calculated & set correctly).

(Original thread was: https://forum.team-mediaportal.com/...ake-up-grap-epg-record-scheduled-shows-41999/ , it can be ignored)

TV-Server Version: 1.0 RC1 SVN 19574
MediaPortal Version: 1.0 RC1 SVN 19574
MediaPortal Skin: BlueTwo Wide
Windows Version: Windows XP SP3
CPU Type: Intel E8200 2.66GHz
HDD: Seagate IV 40GB
Memory: Corsair 2GB 800MHz
Motherboard: Asus P5E-VM HDMI
Video Card: Intel X3500 IGP HDMI
Video Card Driver:
Sound Card: Realtek HD Integrated
Sound Card AC3: AC3Filter
Sound Card Driver:
1. TV Card: FireDTV DVB-C
1. TV Card Type:
1. TV Card Driver:
2. TV Card:
2. TV Card Type:
2. TV Card Driver:
3. TV Card:
3. TV Card Type:
3. TV Card Driver:
4. TV Card:
4. TV Card Type:
4. TV Card Driver:
MPEG2 Video Codec: nVidia Purevideo
MPEG2 Audio Codec: AC3Filter
h.264 Video Codec: CoreAVC 1.7
Satelite/CableTV Provider:
HTPC Case: Antec Fusion 2
Cooling: Stock
Power Supply: Antec 430W
Remote: Logitech diNovo Mini / FireDTV Remote
TV: Toshiba 46ZF355
TV - HTPC Connection: HDMI

 

[tourettes]

I have seen that same error in logs from time to time, but I newer have seen any issues that are caused by it.

 

[seco]

For me the issue is that (scheduled) wake up doesn't work anymore, it worked fine in 0.2.3.0.

I don't fully understand how this should work.

There is a line
2008-07-08 18:15:35.703125 [Powerscheduler Suspender]: PowerScheduler: Set wakeup timer to wakeup system in 1424,15494791667 minutes

in the tv.log which seems to be correct.

But when PowerEventThread is running the same code and the error occurs, execution never reaches that point because of the NPR.

So what happens to wakeup timer then? If it's not calculated & set correctly because of the NPR, the wake up doesn't work? In any case, I'd consider this as a bug.

 

[seco]

Powerscheduler.cs OnPowerEvent():

case PowerEventType.StandBy:
_denySuspendQuery = true; // reset the flag

Log.Debug("PowerScheduler: System is going to standby");
_standby = true;
_timer.Enabled = false;
_controller.EpgGrabberEnabled = false;
FreeTVCards();
SendPowerSchedulerEvent(PowerSchedulerEventType.EnteringStandby, false);
SetWakeupTimer();
return true;

Is the call order causing the problem?

FreeTVCards(); ---> DeInits controller which stops the plugin -> _powerManager is set to null
SendPowerSchedulerEvent(PowerSchedulerEventType.EnteringStandby, false); ---> Dunno what effects this has
SetWakeupTimer(); ---> _powerManager is used here --> NullReferenceException


EDIT:

In my opinion SetWakeupTimer(); call should not be in OnPowerEvent() method because it is already called before by PowerScheduler Suspender thread.

 

[tourettes]

...waiting for Bavarian to check this out

 

[seco]

Wake up is working for me now but I don't know why. I don't use any modified Powerscheduler.dll at the moment so I still get the NullReferenceException to error.log every time when entering to standby but the wake up seems to be fine at least with scheduled recordings.

Only thing I did was that I turned Intel EIST and C1E modes on in BIOS.

Anyway, NPR is still a bug that should be fixed. I don't know does it effect the wake up timer somehow.

I'll do more testing with EIST & C1E settings when I come back from Miami next week. I also have a new problem now when wake up is working. I use "Restart Mediaportal when resuming from standby" option and because of that I get Windows error message saying something that "Invalid window handle" when resuming from standby. When I close the error dialog, MP restarts up fine.

 

[Bavarian]

Hi seco,

I have fixed the problem. Please give attached PowerScheduler.dll a try. With this dll the problem should be gone.


Bavarian

 

[seco]

Hi seco,

I have fixed the problem. Please give attached PowerScheduler.dll a try. With this dll the problem should be gone.


Bavarian

Hi Bavarian!

I tried the attached PowerScheduler.dll but the error remains.

1. Going to sleep and wake up was fine, so both of those are working.

2. BUT, For some reason, the scheduled recording didn't start at all!

3. NPR error is still in the error.log

I really wonder why the recording didn't start and was it caused by the modifications that you made, sounds very unlikely. I can see the recording in the "Scheduled" listing but it's not recording. I tried to record "Tulosruutu" at 22.20

Logs attached.

 

[seco]

Final test run,

Settings:

1. TV-Server reinitialize after wake up OFF

2. Mediaportal restart after wake up ON

Steps:

1. Computer starts up, MP starts up automatically

2. I go to MyTV and schedule a recording through EPG

3. I return to Home screen and wait 5 minutes for shutdown

4. Shutdown occurs

5. Wake up occurs, recording is started automatically

6. I tune to few channels

7. I stop TV, delete recording that is going on, recording is stopped

Results:

1. Everything is working GREAT! No NRE in error.log anymore.

 

[seco]

Bavarian,

I'm curious what changes did you make? Will those be in SVN at some point?

Also do you yet know what is causing the TVServer re-initializing fail if it has been turned ON in configuration?