We have a 64 Bit .Net Application which is a Windows Form. The UI has a Live Video display which shows every Frame from a USB Camera using a delegate eventhandler. Frames are sent to this UI at 60 frames /sec.
We have a need to stop the Live update whenever Windows Locks out due to the screen saver settings.
Code is all in C#.
We do know that the SystemEvents.SessionLock/Unlock does the trick for us. OR we could also use the WM_WTSSession_CHANGE through the WTSRegisterSessionNotification API's. Either way it is supposed to do the same work of letting the UI know that Windows has Locked or Unlocked.
All good so far.
The issue is when the Live Video is being updated, the SessionChange Events never gets to the WndProc() method or the SystemEvents SessionSwitch eventhandler.
If I stop the Frame updates, then the events work perfectly fine.
Yes the Frames being updated are on the GUI Thread using the InvokeRequired checks.
Result is the App crashes when Windows Locks out, because we didn't process the events in 5secs(MS recommendation). I have tried many options of getting it to process the events with some luck however its very inconsistent.
This is a kind of threading issue where the Frames updating is not allowing the Session events to be processed.
Any ideas on how we can look into these session events before Frame updates? or on how do we solve this so the UI can process the Session events?
Your suggestions are much Appreciated.
Update:
If I force a lock(click Ctrl+Alt+Del) and log back in the Session Events are received. Just does not happen on Screen saver Lock.
Related
I want to capture a stacktrace of an application which sometimes stops responding for few minutes.
When the application stops responding, the windows desktop also stops responding to mouse clicks, although some other already running applications are working fine at that time (for example windbg works fine, ProcessExplorer refreshes its screen, but does not respond to mouse events).
While the application is non responsive, it is actually taking about 80% of one CPU core. That is why I would like to get a stacktrace.
The misbehaving application usually takes about 2-3 minutes to do its strange job or if Ctrl+Esc is pressed it becomes responsive immediately (and the start menu opens of course...)
I have WinDbg attached to the misbehaving application and when I issue the Break command, the break-in does not happen until the application starts to respond again.
From what I understand the break-in actually creates a remote thread which pretty soon calls DbgBreakPoint.
What could be preventing debugger's thread from executing?
EDIT:
First of all thanks for your help!
I was also thinking that this might be caused by a bad device driver or something that installs a system wide hook somewhere.
I was thinking to enable kernel debugging and get a stack trace from the kernel for the offending thread or enable manual bluescreen trigger to produce a dump and look at that afterwards.
Process Explorer and Process Monitor does not reveal anything interesting. They also become unusable when the bug is triggered (updating their windows but not responsive to mouse or keyboard).
EDIT2:
Background info:
App uses QT, OpenGL and also DirectSound and runs on Windows 7 SP1 x64
I am currently suspecting something with the graphics part.
The strange thing is that if a system-wide lock is taken (like GDI Lock), this would prevent drawing of other Windows, but that does not happen. WinDbg on same machine works fine. ProcessExplorer updates but does not receive mouse clicks, Desktop updates but no mouse clicks.
I currently have a kernel debugger attached...
EDIT3
ETW was most useful for debugging. It turns out that Qt's main event processing loop goes crazy. PeekMessage and MsgWaitForMultipleObjectsEx (with 0 timeout) gets called in a tight loop. That is where the high CPU usage comes from.
It looks like the App is generating/getting loads of messages at that time. But it is not easy to see what the messages are (or I don't know how to access function parameters in ETW). Using a debugger also does not help much but, with a breakpoint in the QT's event loop leads me to believe that WM_TIMER messages are the culprit.
Given that the desktop also misbehaves during this time, it sounds like your app isn't necessarily misbehaving but merely aggravating a bug elsewhere (e.g., in a device driver or some crummy anti-malware code that has injected itself into other processes). Stack traces from your app may or may not be very revealing.
If the problem is easily reproducible, I'd set a breakpoint somewhere in the "middle" of the app and see if the problem happens before or after that. Then move the breakpoint until you find the last instruction your app executes before things go bonkers. Figuring out what your app does that triggers this behavior may give a clue as what's going on.
Another option is to try using some system-wide debugging tools. First, I'd peak in the Event Viewer to see if there are suspicious error or warning events posting in proximity to the moment the machine goes haywire. Then I'd try a tool like Sysinternal's Process Monitor or Process Explorer to get a better view of what's happening. You might also try ETW to capture a system-wide trace of what's happening on the system that you can study after the fact. (ETW can be hard to use, so check out Bruce Dawson's UIforETW.)
Use ETW to find the cause. Install the Windows Performance Toolkit (part of the Win10 v1511 SDK: https://go.microsoft.com/fwlink/p/?LinkID=698771 which is the last version that works in Win7), run WPRUI.exe, select CPU Usage and click on Start.
After you captured the hang, click on Save. Wait until WPRUI is finished, open the ETL in WPA, setup and load debug symbols in WPA.
Drag & Drop the CPU Usage (Precise) graph to analyse pane and look for WAIT (µs) max for your process to see that long hang and expand the stack to see where it happens.
My Windows Phone XNA game calls Guide.BeginShowKeyboardInput to get the user's name. While the Guide's input screen is shown, if the user presses the Home or Search (hardware) buttons, the game is deactivated as usual - but if the user then presses the Back (hardware) button, the game should resume but it doesn't. Instead it shows the "Resuming..." message until Windows Phone gives up trying to resume the game and kills the process.
Please note:
My app is failing Microsoft certification because of this problem - I really need to fix it!
This only happens in my game when the Guide input screen is shown - when it's not shown, the game
resumes properly after being deactivated.
This problem only occurs when the game is run on WP7.x (verified problem on WP7.5 and
WP7.8) - although the game seems to resume properly on WP8 devices.
I've created a blank XNA game project, called Guide.BeginShowKeyboardInput and tested it using WP7.x devices, and this problem-behavior doesn't occur.
I've tested the game without enabling Music & my Trial License manager (they use timers) and it still does this.
Exact same behavior occurs in the emulator (resume-failure on WP7.x emulators, works fine on WP8
emulator)
I used threads to asynchronously download content during the loading screen - but they already completed and exited.
I don't believe other threads are running, although this seems like
it could be a thread-blocking issue.
Any other ideas on what could be blocking the game from resuming when the Guide.IsVisible or how to debug/resolve this problem?
The solution to this issue was simply to NOT use SuppressDraw when dealing with any operation that passes control outside of the app, e.g. Launchers, Choosers and the Guide.
Have you tried calling "Guide.EndShowKeyboardInput" in either the Deactivating or closing events?
So that the guide is closed before the app suspends, you do get 10 seconds to suspend so this might be worth looking into.
If you want the guide to re-show on resume, then in your state saving code just have a flag and open the guide if it's set.
I've got an Adobe AIR application written in pure AS3 that has some functionality that happens when the user is idle and then returns to the normal state when the user returns. I'm detecting this activity with the following code:
NativeApplication.nativeApplication.idleThreshold = 180;
NativeApplication.nativeApplication.addEventListener(Event.USER_IDLE, onUserIdle);
NativeApplication.nativeApplication.addEventListener(Event.USER_PRESENT, onUserPresent);
The onUserIdle method is called after 3 minutes as it should be, but then the onUserPresent event is fired almost immediately afterwards. I'm talking milliseconds later. This happens without any user input whatsoever. The bizarre thing is that this does not occur on Windows - only on OSX. And it happens on all flavors of OSX going back to 10.6.3.
Adobe's documentation is incredibly vague on how those events are determined, so I'm not sure if there is something I can do at the system level to fix the problem. Does anyone have any experience with this issue, and if not, any other suggestions on how I can detect user idleness even when the app does not have focus?
Just to preempt the suggestion, I cannot use mouse/keyboard listeners to simulate the same behavior because they do not work if the application loses focus, whereas the NativeApplication events still fire. I've also used NativeProcess to get the output of ioreg to get the hardware idle time as reported by the system, but it does not appear to be affected by the mouse.
I really appreciate any assistance.
Edit: I just discovered that this does not occur when the application is run in an Administrator account on OSX. It only happens in a User account, which only serves to confuse me more.
I figured out what the issue is. When the USER_IDLE event is fired in a user account, we did several things - one of which was forcibly kill the Dock in order to make sure it was hidden from the screen. For whatever reason, this resets the internally available idleThreshold count. This was not only happening in AIR - it was also happening when monitored through Terminal and it appears there is absolutely nothing that can be done to stop it. The solution was to stop killing the dock. Everything magically worked after that.
I currently have a "dumbphone", but I'm trying to make an app that'll time and store the call duration of incoming calls for windows 7.1 ("7.5") phones, for the user scheduling purposes.
However, after extensive searching and googling, with topics like this one:
Windows Phone 7 - How to calculate call duration or termination
it seems that the Windows 7/7.1 SDK does not allow access to recognizing when a call is coming in. I've read about obscure and unobscure, but that this wouldn't be a good idea since it would start the timer anytime the UI hides the program, not just calls.
I've thought that maybe I could just pull the call duration or the start/end time from the call history, but windows 7 SDK doesn't support that either it seems.
So I decided to seek help. Is there a way to make this work? Is there some clever way to recognize when a call is incoming and stopped? Or some clever way to pull call times/durations? Or maybe a way to detect when the user presses that "accept incoming call" button? Or maybe a way to single out when a call is obscuring the UI?
Any help would be greatly appreciated. Thank you
Due to security reasons your application does not have any kind of accsess to call history ect. So you are in a sendbox and you don't know nothing about phone calls.
From the Windows Phone SDK, there is no way to achieve this!
The only thing I can think of is that when a call comes, the current app gets notified that is now Obscured because a new screen is now on top of it (the caller ID screen), and will get notified when it gets back to focus.
But the truth is that this happens even if a SMS message notification pops on the screen and the user taps to read it, or some app gets a notification pushed...
I am in the process of porting a Flash Player-based game over to the Desktop (OSX and Windows) via Adobe AIR (3.1). The porting to AIR itself has gone rather smoothly. The one wrinkle I've been dealt is that the game will be distributed over the Steam network. In order to interact with the Steam Client, I've had to write a native extension to expose the Steam SDK APIs to AS3. The native extension support has been implemented for both platforms, and I have the application launching and communicating with Steam as desired.
The area I've run into trouble is dealing with Steam's Overlay, which renders overtop of games when it is activated. Essentially, when a game is launched, the Steam Client suspends the process in order to hook its Overlay library up to either D3D or OpenGL. Initially, the Overlay failed to appear at all as the AIR application descriptor had the default rendermode set to "auto." However, once I switched the rendermode to "gpu" the Overlay would appear as desired.
On the OSX side of things, everything works as expected. I can toggle in and out of the Overlay just fine. On the windows end of the spectrum, I've hit a bit of a problem when I activate the Overlay. Specifically, when the Overlay is enabled (it's rendering overtop of the game) and I either move the mouse or generate keyboard input, both the Overlay and the game both "freeze" (rendering stops) for 2-3 seconds. Additionally, I have noticed that when I open the Task Manager with the game running, the cpu usage is roughly 75-80%. The cpu usage remains the same when I first active the Overlay (which is desired). However, when I move the mouse cursor or press a key on the keyboard, the cpu usage drops to roughly 1%. This problem has occurred on 4 of 5 windows machines (2 XP, 3 Win 7) we've tested on. Naturally, I first contacted Valve about the issue since this only occurs when the Overlay is enabled. I've uploaded both the OSX and Windows builds for their devs to debug; however, my contact suggested I find out more about AIRs rendering/input as well.
Here is a snippet of a post with a Steam Dev detailing how the overlay works:
"The requirements for the overlay on Windows are as follows:
Game must use D3D7, D3D8, D3D9, D3D10, D3D11, or OpenGL
Game must call D3D Present() or OpenGL SwapBuffers() on a fast regular basis (these calls are hooked by the overlay and give it opportunity to do work). For instance 2D games that only call these functions when mouse movement occurs or graphics on screen actually change rather than every frame will not function well.
Game should use standard Win32 input messages, raw Win32 input messages, or DirectInput for input and the overlay will then detect hotkeys and hide/block input events from the game when active.
It sounds like your game may violate #2 and stops calling Present/SwapBuffers sometimes when the overlay is active. This may happen if you call these functions in response to user input which is now blocked due to the overlay being activated. You should guarantee you keep pumping frames and swapping at a regular interval even if input events aren't occurring."
After a little more prodding, the Valve devs profiled my application to determine if there was any specific problem occuring with the Game Overlay. Unfortunately, they were unable to find anything going on in the Overlay itself. This pretty much means that AIR on Windows doesn't like that the Overlay is blocking Win32 input messages. Here is the Valve dev's response:
"I got your depots and did some testing. Nothing unusual happens in the overlay. Profiling your app with xpref while the issue occurs and taking some minidumps to check callstacks it looks like the app just blocks up completely and uses zero CPU during the time it is blocked, when it happens it calls Present() only at roughly 1 second intervals until it recovers (maybe there is a 1 second timeout somewhere in the AIR code). It's hard to get much detail since I don't have any symbols for the AIR runtime libraries.
It does however look like this is somehow related to input state and AIR being unhappy with win32 input messages stopping. If I change our overlay to not block any input at all once activated (which obviously has some pretty big problems for usability, but just for testing purposes.) then the issue does not occur. It's possible that the AIR code has some weird logic where if it's seen some specific WM_WHATVER message it's expecting another right after and blocks on it waiting somehow.
Hopefully you can work out on your side or with Adobe as to why the application behaves badly in these situations and starts blocking and not presenting at regular intervals."
I've posted on the Adobe forums, but haven't had any such luck over there. Mainly, I'm hoping that someone has either dealt with this before or has an idea about how I could possibly get around the issue. Any suggestions, comments or thoughts would be greatly appreciated!
As it turns out, there is an bug deep in AIR core framework that is the root cause of this issue. Adobe has confirmed the bug, and they are working on a fix for the Cyril (AIR 3.3) release. The status of the bug (#3089755) can be viewed in the Adobe AIR bug list.
In the short-term, I was forced to detect Windows messages that were being consumed by the SteamOverlay, and pass on fake messages to prevent AIR from locking up. I accomplished this by using the Windows API SetWindowsHookEx along with the WH_DEBUG and WH_GETMESSAGE hooks. This is definitely not a desirable approach, but was needed in the short-term until Adobe releases a fix.