Re: [PATCH 2/2] exa: do PrepareAccess for classic too, since we do need to map the frontbuffer.

[Ben Skeggs <skeggsb-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On Thu, 2009-02-26 at 21:55 +0100, Maarten Maathuis wrote:
> - I'm surprised we didn't get serious complaints about not being able to render to the frontbuffer.
We don't get serious complaints because it's not an issue.  EXA is given
the virtual address, and it remembers it.  The design of the mm
guarantees the virtual address of the buffer won't change, map()/unmap()
are there merely for synchronisation of CPU/GPU access.

In the "classic" case, exaMarkSync()/exaWaitSync() do the
synchronisation job as we don't use prepare/finish_access().

Ben.

> ---
>  src/nouveau_exa.c |   16 ++++++++++------
>  1 files changed, 10 insertions(+), 6 deletions(-)
> 
> diff --git a/src/nouveau_exa.c b/src/nouveau_exa.c
> index 20ad380..4b21e80 100644
> --- a/src/nouveau_exa.c
> +++ b/src/nouveau_exa.c
> @@ -265,12 +265,14 @@ nouveau_exa_wait_marker(ScreenPtr pScreen, int marker)
>  static Bool
>  nouveau_exa_prepare_access(PixmapPtr ppix, int index)
>  {
> -	ScrnInfoPtr pScrn = xf86Screens[ppix->drawable.pScreen->myNum];
> +	ScreenPtr pScreen = ppix->drawable.pScreen;
> +	ScrnInfoPtr pScrn = xf86Screens[pScreen->myNum];
>  	NVPtr pNv = NVPTR(pScrn);
>  
> -	if (pNv->exa_driver_pixmaps) {
> +	if (pNv->exa_driver_pixmaps || pScreen->GetScreenPixmap(pScreen) == ppix) {
>  		void *map = nouveau_exa_pixmap_map(ppix);
>  
> +		/* Really bad if this is the frontbuffer. */
>  		if (!map)
>  			return FALSE;
>  
> @@ -284,10 +286,11 @@ nouveau_exa_prepare_access(PixmapPtr ppix, int index)
>  static void
>  nouveau_exa_finish_access(PixmapPtr ppix, int index)
>  {
> -	ScrnInfoPtr pScrn = xf86Screens[ppix->drawable.pScreen->myNum];
> +	ScreenPtr pScreen = ppix->drawable.pScreen;
> +	ScrnInfoPtr pScrn = xf86Screens[pScreen->myNum];
>  	NVPtr pNv = NVPTR(pScrn);
>  
> -	if (pNv->exa_driver_pixmaps)
> +	if (pNv->exa_driver_pixmaps || pScreen->GetScreenPixmap(pScreen) == ppix)
>  		nouveau_exa_pixmap_unmap(ppix);
>  }
>  
> @@ -553,8 +556,6 @@ nouveau_exa_init(ScreenPtr pScreen)
>  		exa->pixmapPitchAlign = 64;
>  
>  		exa->PixmapIsOffscreen = nouveau_exa_pixmap_is_offscreen;
> -		exa->PrepareAccess = nouveau_exa_prepare_access;
> -		exa->FinishAccess = nouveau_exa_finish_access;
>  		exa->CreatePixmap = nouveau_exa_create_pixmap;
>  		exa->DestroyPixmap = nouveau_exa_destroy_pixmap;
>  		exa->ModifyPixmapHeader = nouveau_exa_modify_pixmap_header;
> @@ -604,6 +605,9 @@ nouveau_exa_init(ScreenPtr pScreen)
>  		exa->maxY = 2048;
>  	}
>  
> +	exa->PrepareAccess = nouveau_exa_prepare_access;
> +	exa->FinishAccess = nouveau_exa_finish_access;
> +
>  	exa->MarkSync = nouveau_exa_mark_sync;
>  	exa->WaitMarker = nouveau_exa_wait_marker;
>