On Mon, 29 Jun 2009 16:07:02 +0000 (GMT) Nicolas Cadio <nicolas.ca...@ymail.com> wrote:
> I use the i915 and DRI2. > I find the error of this problem, the path to open the lib > i915_dri.so was bad in the > file ..../mesa-7.4.0-1/src/mesa/src/glx/x11/dri_common.c. > > Now, I can use this demo with the option "-s s" (sgi_video_sync), but > with the option "-s b"(double buffers), there isn't vertical sync, > and I don't find why? > > I have noticed that the drivers calls just once the function > drm_wait_vblank > (.../linux-kernel-2.6.26-x/src/drivers/gpu/drm/drm_irq.c) with the > option "-s b" whereas it is called many times with "-s s". Is it > normal ??? That's exactly why this test exists. :) Implementing vblank synchronized buffer swaps (used by the -sb option) is up to the driver. In the Intel stack, we implement it in our DRI2 CopyRegion hook, waiting for the display scanline to be outside of the region to be copied (I think radeon has been doing this for even longer). A page flipping or compositing manager solution could achieve the same thing, probably with higher performance. With the -ss option, the glsync app actually does a vblank wait using the SGI vsync extension before every fill, so you should see a lot of those in your debug output if you look, whereas -sb may or may not do that, depending on your driver implementation of swapping. -- Jesse Barnes, Intel Open Source Technology Center ------------------------------------------------------------------------------ _______________________________________________ Mesa3d-dev mailing list Mesa3d-dev@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
