On Tue, Sep 23, 2014 at 1:46 PM, Eric Nelson < [email protected]> wrote:
> Hi Carlos, > > On 09/23/2014 10:52 AM, Carlos Rafael Giani wrote: > > > > I wonder why it is single buffered. is it because of the memory > > consumption for a second buffer? The buffers could be flipped, > > eliminating any need for blits, so the memory bandwidth should not be an > > issue. > > > > There is a memory bandwidth implication. > > Assuming frame buffers A and B in a double-buffered system, > rendering will occur into B while A is displayed, then the > two will be swapped, such that B is displayed and A is the > new rendering output. > > In order for apps to only update parts of their windows, any > "dirty" blocks need to be copied from B to A in the process > of the flip. > > > On 2014-09-23 18:48, Prabhu S wrote: > >> i.MX6 X11 EGL is single buffered and there is no support for VSYNC. > >> The tearing with X11 is a known issue. We did investigate to fix this, > >> but the solution becomes too hacky and cannot be used in production > >> systems. > >> > >> We are adding VSYNC support in Wayland. eglSwapInterval will be > >> supported for FBDEV and Wayland backends in the upcoming release(in > >> january). So Ozone-wayland can take advantage of this. > >> > > ?? This is already supported in Wayland, though it is controlled > by an environment variable. > export FB_MULTI_BUFFER=2. By doing this server side is VYSNC controlled. The client side support in next release. > > You can see it in action by watching /sys/class/graphics/fb0/pan. > > Regards, > > > Eric >
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