[PATCH 2/7] composite: Add exception mechanism for implicit redirection policy

[Jasper St. Pierre]

Does this mean this mean that reparenting an RGB24 visual window into an
ARGB32 visual window will only be copy-free on Xwayland and not Xorg?


On Tue, Apr 1, 2014 at 2:53 AM, Kristian Høgsberg <krh at bitplanet.net> wrote:

> Normally composite will decide to add implicit redirection when a
> window with an alternate visual is a parent of a window with a regular
> visual or vice versa.  This uses extra pixmap memory and incurs an extra
> copy.  This exception mechanism provides a way for a DDX to override this
> if the DDX knows that its acceleration architecture will render correctly.
>
> The relevant case is that of an RGB window reparented into a ARGB parent
> frame window.  If the DDX knows that the acceleration architecture in use
> will pad the alpha channel to opaque when rendering to the RGB window,
> the implicit redirection can be avoided.
>
> This patch adds a new composite function:
>
>   CompositeRegisterImplicitRedirectionException()
>
> which lets a DDX register a pair of parent and child window visuals, that
> will not be implicitly redirected even if the normal policy would have
> made that choice.
>
> Signed-off-by: Kristian Høgsberg <krh at bitplanet.net>
> Reviewed-by: Keith Packard <keithp at keithp.com>
> ---
>  composite/compinit.c     | 24 ++++++++++++++++++++++++
>  composite/compint.h      |  7 +++++++
>  composite/compositeext.h |  4 ++++
>  composite/compwindow.c   | 18 ++++++++++++++++++
>  4 files changed, 53 insertions(+)
>
> diff --git a/composite/compinit.c b/composite/compinit.c
> index 1db9e0b..48e938f 100644
> --- a/composite/compinit.c
> +++ b/composite/compinit.c
> @@ -229,6 +229,28 @@ CompositeRegisterAlternateVisuals(ScreenPtr pScreen,
> VisualID * vids,
>      return compRegisterAlternateVisuals(cs, vids, nVisuals);
>  }
>
> +Bool
> +CompositeRegisterImplicitRedirectionException(ScreenPtr pScreen,
> +                                              VisualID parentVisual,
> +                                              VisualID winVisual)
> +{
> +    CompScreenPtr cs = GetCompScreen(pScreen);
> +    CompImplicitRedirectException *p;
> +
> +    p = realloc(cs->implicitRedirectExceptions,
> +                sizeof(p[0]) * (cs->numImplicitRedirectExceptions + 1));
> +    if (p == NULL)
> +        return FALSE;
> +
> +    p[cs->numImplicitRedirectExceptions].parentVisual = parentVisual;
> +    p[cs->numImplicitRedirectExceptions].winVisual = winVisual;
> +
> +    cs->implicitRedirectExceptions = p;
> +    cs->numImplicitRedirectExceptions++;
> +
> +    return TRUE;
> +}
> +
>  typedef struct _alternateVisual {
>      int depth;
>      CARD32 format;
> @@ -349,6 +371,8 @@ compScreenInit(ScreenPtr pScreen)
>
>      cs->numAlternateVisuals = 0;
>      cs->alternateVisuals = NULL;
> +    cs->numImplicitRedirectExceptions = 0;
> +    cs->implicitRedirectExceptions = NULL;
>
>      if (!compAddAlternateVisuals(pScreen, cs)) {
>          free(cs);
> diff --git a/composite/compint.h b/composite/compint.h
> index 12dc8b3..56b76c5 100644
> --- a/composite/compint.h
> +++ b/composite/compint.h
> @@ -119,6 +119,11 @@ typedef struct _CompOverlayClientRec {
>      XID resource;
>  } CompOverlayClientRec;
>
> +typedef struct _CompImplicitRedirectException {
> +    XID parentVisual;
> +    XID winVisual;
> +} CompImplicitRedirectException;
> +
>  typedef struct _CompScreen {
>      PositionWindowProcPtr PositionWindow;
>      CopyWindowProcPtr CopyWindow;
> @@ -155,6 +160,8 @@ typedef struct _CompScreen {
>      CloseScreenProcPtr CloseScreen;
>      int numAlternateVisuals;
>      VisualID *alternateVisuals;
> +    int numImplicitRedirectExceptions;
> +    CompImplicitRedirectException *implicitRedirectExceptions;
>
>      WindowPtr pOverlayWin;
>      Window overlayWid;
> diff --git a/composite/compositeext.h b/composite/compositeext.h
> index 0b148f0..b96cb1d 100644
> --- a/composite/compositeext.h
> +++ b/composite/compositeext.h
> @@ -35,6 +35,10 @@ extern _X_EXPORT Bool
> CompositeRegisterAlternateVisuals(ScreenPtr pScreen,
>                                                          VisualID * vids,
>                                                          int nVisuals);
>
> +extern _X_EXPORT Bool
> CompositeRegisterImplicitRedirectionException(ScreenPtr pScreen,
> +
>  VisualID parentVisual,
> +
>  VisualID winVisual);
> +
>  extern _X_EXPORT RESTYPE CompositeClientWindowType;
>
>  #endif                          /* _COMPOSITEEXT_H_ */
> diff --git a/composite/compwindow.c b/composite/compwindow.c
> index 6c24349..8824294 100644
> --- a/composite/compwindow.c
> +++ b/composite/compwindow.c
> @@ -336,6 +336,21 @@ compIsAlternateVisual(ScreenPtr pScreen, XID visual)
>  }
>
>  static Bool
> +compIsImplicitRedirectException(ScreenPtr pScreen,
> +                                XID parentVisual, XID winVisual)
> +{
> +    CompScreenPtr cs = GetCompScreen(pScreen);
> +    int i;
> +
> +    for (i = 0; i < cs->numImplicitRedirectExceptions; i++)
> +        if (cs->implicitRedirectExceptions[i].parentVisual ==
> parentVisual &&
> +            cs->implicitRedirectExceptions[i].winVisual == winVisual)
> +            return TRUE;
> +
> +    return FALSE;
> +}
> +
> +static Bool
>  compImplicitRedirect(WindowPtr pWin, WindowPtr pParent)
>  {
>      if (pParent) {
> @@ -343,6 +358,9 @@ compImplicitRedirect(WindowPtr pWin, WindowPtr pParent)
>          XID winVisual = wVisual(pWin);
>          XID parentVisual = wVisual(pParent);
>
> +        if (compIsImplicitRedirectException(pScreen, parentVisual,
> winVisual))
> +            return FALSE;
> +
>          if (winVisual != parentVisual &&
>              (compIsAlternateVisual(pScreen, winVisual) ||
>               compIsAlternateVisual(pScreen, parentVisual)))
> --
> 1.9.0
>
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> xorg-devel at lists.x.org: X.Org development
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-- 
  Jasper
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