On Sun, Oct 20, 2002 at 05:09:08PM -0600, Jens Owen wrote: > Ian Romanick wrote: > > Warning: ignorant questions on the way... > > > > I've gotten some questions from a couple of people about backing store with > > DRI, on the R100 driver specifically. Because my background isn't firmly > > rooted in X-Windows, I wasn't really familiar with what that meant. :) I > > did a little searching, and I think I have a vauge idea now. > > > > In any case, as near as I can tell, when the Radeon DRI driver gets loaded, > > backing store is explicitly disabled. Why is that? Is it a hardware > > limitation or is it "just" to conserve memory? Something else? > > Ian, > > Sorry about the late response. I hope this is still useful. > > Backing Store is a "feature" in X that allows the contents of windows to > be preserved even when they are obscured. The benefit of this feature > is the application should not receive expose events from the server when > a window is uncovered. However, the implementation of backingstore > within the X Server puts the burden on the drivers to render to both the > exposed areas on the screen *and* to the saved areas of backing store > which I belive are implemented as a pixmap...which can reside in > offscreen memory or the X Server's system allocated memory.
Okay, that's pretty much what I thought it did. There was a similar feature in the Amiga windowing system back in the day, but I won't go there. :) > Making a direct rendering 3D driver render to a windows backing store > area is a complicated task with very little benefit, IMO. Right, but shouldn't purely 2D targets work? I wouldn't think that the menus in twm are using OpenGL. :) At the very least, if it's not supported at all, when X is started with +bs, shouldn't it say just say no? That's the problem that I see. The user requests a feature, X says it's okay, but then it's not implemented. -- Smile! http://antwrp.gsfc.nasa.gov/apod/ap990315.html _______________________________________________ Xpert mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/xpert
