[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 » Sun Nov 09, 2014 10:40 pm

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: 2157
Joined: Fri Feb 17, 2012 3:20 am

Re: xcb_xlib_too_much_data_requested workaround

Post by agw » Fri Nov 21, 2014 2:27 pm

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.

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