FrontEnd hangs when OSD is displayed while Teletext captions are enabled

[anonymous]

System uses XVMC for display. While watching a show, if closed captions (provided by Teletext page 801) are enabled and then do FF or REW multiple times the display hangs.

The problems comes from a semaphore deadlock. What happens is that new teletext data is received and hence results in the osdtypesteletext m_lock being locked. At the same time XVMC has to redraw the OSD so it locks the osdlock. The OSD display process then calls the Teletext draw function who will now hang since it requires the osdtypesteletext m_lock. Also since the teletext had received new data it calls the OSD::UpdateTeletext function which results in the hang since it also needs to lock osdlock.

[pholmes@…]

Patch for FrontEnd lockup

[danielk]

Code reviewed + updated patch (still untested)

[danielk]

I'm going to send Frank Muenchow a note about this ticket before I do anything further with this patch...

[danielk]

(In [13539]) Fixes #3433. Fixes a deadlock in teletext parser/renderer.

The patch is from pholmes at india dot com, and was reviewed and tested by Frank Muenchow.

The nature of the deadlock is described in the ticket.