2011/9/2 Stéphane Marchesin <stephane.marche...@gmail.com>: > 2011/9/2 Jose Fonseca <jfons...@vmware.com>: >> ----- Original Message ----- >>> Hi, >>> >>> While debugging some code I ran across the following situation: >>> >>> - pipe_context c1 is created >>> - pipe_surface s1 is created >>> - strb-> surface is set to s1 (s1's refcount goes up) >>> - pipe_context c1 is destroyed >>> - strb is destroyed >>> - strb->surface is destroyed (so s1's refcount is now 0 and we want >>> to >>> destroy it) >>> >>> At that point s1 references c1 which is not available any more, so >>> when we try to call ctx->surface_destroy to destroy s1 we crash. >>> >>> We discussed this a bit on IRC, and we agreed that the proper >>> solution, since surfaces outlive their context, is to make surfaces >>> screen-bound instead. I'm going to implement that unless someone >>> objects. >>> >>> As a side note, the same issue will happen with sampler_views, so >>> it'll get a similar fix. >> >> Sampler views and surfaces were previously objects bound to screen, and we >> changed that because of poor multithreading semantics. Per-context sampler >> views / render targets actually matches the 3D APIs semantics better, so I >> don't think that reverting is the solution. >> >> It looks to me that the issue here is that pipe_context should not be >> destroyed before the surfaces. strb->surface should only be used by one >> context, and should be destroyed before that context is destroyed. >> >> IIUC, strb matches GL renderbuffer semantics and can be shared by multiple >> context. If so, strb is treating pipe_surfaces as a entity shareable by >> contexts when really shouldn't. >> >> The solution is: >> - strb can only have pipe_resources, plus the key for the surface (face, >> level, etc) >> - the pipe_surfaces that are derived should be stored/cached in the >> GLcontext. >> - when the GLcontext / pipe_context is being destroy, the pipe surfaces can >> be destroyed before >> > > I don't understand some of it. From what I see, it should be enough, > whenever strb binds a surface, to add a pointer to this strb to a > list of strb's to the pipe_context. By doing that, we would be able to > unbind the surfaces from the strb before we destroy the context. > However, pipe_context structures can't reference gl structures, so how > would you solve that? > > Also, what difference does it make if strb's only have pipe_resources? > And why do I need a key? > > This all is definitely more complex than it should be. >
And, yeah, I have a much simpler solution in mind, which I might just end up doing for my own use: - remove the ctx arg to surface_destroy() - add a destroy function pointer to pipe_surface - call that instead of going through the ctx when we destroy the surface Stéphane _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
