On Tue, 2009-03-17 at 03:56 -0700, José Fonseca wrote: > On Tue, 2009-03-17 at 03:39 -0700, Thomas Hellstrom wrote: > > Thomas Hellström wrote: > > > Hi! > > > > > > I'm currently looking into the thread-safety of the dri drivers. In > > > particular the calls to libX11. > > > > > > It appears that many of the applications I've tried have issues with > > > deadlocks in the XCB code. > > > It looks like this might be an issue with the locking order of > > > XLockDisplay() and driver mutexes. > > > > > > In particular, if the application protects all glx calls with > > > XLockDisplay() the driver might deadlock in a normal GL call: > > > > > > Thread A: > > > XLockDisplay() -> glxXXX -> driver mutex -> Xlib call -> Xcb > > > XLockdisplay(). > > > Thread B > > > Normal GL call -> driver mutex -> Xlib call -> Xcb XLockDisplay(). > > > > > > So we have a locking order reversal between the driver mutex and > > > XLockDisplay which causes a deadlock. > > > > > > Now, it seems like a simple away around this would be to omit the > > > application XLockDisplays() completely. However, that seems to cause > > > issues with XPending and XNextEvent eating the reply data meant for > > > XSync(), leaving XSync waiting locked in a select(). > > > > > > I guess the remedy is to have the DRI utility routines and drivers > > > protect _all_ X calls with XLockDisplay(). > > > > > > Does anyone have thoughts / insights about this? > > > > > > Thanks, > > > Thomas > > > > > > > > > > > Hmm, > > I installed a non-XCB Xlib and all problems just vanished... > > Don't mind the above. > > So is this a XCB problem?
XCB is pretty much the default now & given that it was supposed to resolve the threading issues with old Xlib, I don't think that this means the issue goes away... Keith ------------------------------------------------------------------------------ Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are powering Web 2.0 with engaging, cross-platform capabilities. Quickly and easily build your RIAs with Flex Builder, the Eclipse(TM)based development software that enables intelligent coding and step-through debugging. Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com _______________________________________________ Mesa3d-dev mailing list Mesa3d-dev@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
