[STICKY] xcb_xlib_too_much_data_requested workaround

Bug reports and questions about running Virtual Radar Server on Linux
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eean
Posts: 1
Joined: Sun Nov 09, 2014 10:35 pm

[STICKY] xcb_xlib_too_much_data_requested workaround

Post by eean »

I was getting errors like this on startup:

Code: Select all

mono: xcb_io.c:736: _XRead: Assertion `!xcb_xlib_too_much_data_requested' failed.
Stacktrace:

  at <unknown> <0xffffffff>
  at (wrapper managed-to-native) System.Windows.Forms.X11Keyboard.XCreateFontSet (intptr,string,intptr&,int&,intptr) <0xffffffff>
  at System.Windows.Forms.X11Keyboard.CreateOverTheSpotXic (intptr,intptr) <0x000bb>
  at System.Windows.Forms.X11Keyboard.CreateXic (intptr,intptr) <0x000d7>
  at System.Windows.Forms.X11Keyboard.CreateXicForWindow (intptr) <0x00033>
  at System.Windows.Forms.X11Keyboard.FocusIn (intptr) <0x00097>
  at System.Windows.Forms.XplatUIX11.SetFocus (intptr) <0x000bb>
  at System.Windows.Forms.XplatUI.SetFocus (intptr) <0x0001f>
  at System.Windows.Forms.ContainerControl.SendControlFocus (System.Windows.Forms.Control) <0x00097>
  at System.Windows.Forms.Form.SetVisibleCore (bool) <0x00757>
  at System.Windows.Forms.Control.set_Visible (bool) <0x00032>
  at (wrapper remoting-invoke-with-check) System.Windows.Forms.Control.set_Visible (bool) <0xffffffff>
  at System.Windows.Forms.Application.RunLoop (bool,System.Windows.Forms.ApplicationContext) <0x00327>
  at System.Windows.Forms.Form.ShowDialog (System.Windows.Forms.IWin32Window) <0x008d7>
  at System.Windows.Forms.Form.ShowDialog () <0x0000f>
  at System.Windows.Forms.MessageBox/MessageBoxForm.RunDialog () <0x00073>
  at (wrapper remoting-invoke-with-check) System.Windows.Forms.MessageBox/MessageBoxForm.RunDialog () <0xffffffff>
  at System.Windows.Forms.MessageBox.Show (string,string) <0x0004b>
  at VirtualRadar.WinForms.SplashView.ReportProblem (string,string,bool) <0x0001f>
  at VirtualRadar.Library.Presenter.SplashPresenter.LoadStandingData () <0x001d1>
  at VirtualRadar.Library.Presenter.SplashPresenter.StartApplication () <0x000cb>
  at VirtualRadar.WinForms.SplashView.backgroundWorker_DoWork (object,System.ComponentModel.DoWorkEventArgs) <0x00047>
  at System.ComponentModel.BackgroundWorker.OnDoWork (System.ComponentModel.DoWorkEventArgs) <0x0002f>
  at System.ComponentModel.BackgroundWorker.ProcessWorker (object,System.ComponentModel.AsyncOperation,System.Threading.SendOrPostCallback) <0x000ae>
  at (wrapper runtime-invoke) <Module>.runtime_invoke_void__this___object_object_object (object,intptr,intptr,intptr) <0xffffffff>

xcb_xlib_too_much_data_requested looked like the relevant bit, so I googled around a bit and it seems to be a not-so-uncommon problem with Mono in general. The 'too-much' made me think it might be due to my CPU being too fast with too many cores and creating a race condition. And I think that was the case because pinning it to one CPU "solved" the problem:

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taskset -c 0 mono VirtualRadar.exe 
And then it just started working flawlessly. It was actually kind of confusing, I had started up Virtual Radar, went and started dump1090 and played with its web interface, and then I came back and found Virtual Radar tracking airplanes already lol.
agw
Posts: 2250
Joined: Fri Feb 17, 2012 3:20 am

Re: xcb_xlib_too_much_data_requested workaround

Post by agw »

Thanks for that - I've taken the liberty of turning this post into a sticky and changing the title. I've a feeling that this has been reported before without any satisfactory solution, if forcing it onto a single processor does the job then that'll be handy.
pakon
Posts: 19
Joined: Tue Sep 08, 2020 11:32 am
Location: Berlin, Germany
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Re: [STICKY] xcb_xlib_too_much_data_requested workaround

Post by pakon »

Hey,

what was the error (the missbehavior) of VRS, when the stacktrace occur? In some cases the data feeds of some satelite stations are not shown. In this case, I've to restart the executable.

Cheers,
Pakon
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