[PATCH xserver] present: disable page flip only when a slave crtc is active

[Michel Dänzer]

On 26/01/17 07:13 PM, Qiang Yu wrote:
> 
> @@ -145,7 +157,7 @@ present_check_flip(RRCrtcPtr    crtc,
>          return FALSE;
>  
>      /* Fail to flip if we have slave outputs */
> -    if (screen->output_slaves)
> +    if (screen->output_slaves && present_check_output_slaves_active(screen))
>          return FALSE;
>  
>      /* Make sure the window hasn't been redirected with Composite */
> 

Actually, I'm not sure why we need to check for slave outputs here at
all. Dave, did you run into an actual problem without the check, or was
it just a theoretical concern? The commit log says:

   We shouldn't flip if the secondary adapters are attached to the
   pixmap currently [...]

What circumstances were you thinking of where a slave output would be
attached to (meaning scanning out directly from?) "the pixmap" (which one?)?


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer