source: vbox/trunk/src/VBox/Additions/x11/x11include/xorg-server-1.4.2/exa.h

/*
 *
 * Copyright (C) 2000 Keith Packard
 *               2004 Eric Anholt
 *               2005 Zack Rusin
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation, and that the name of copyright holders not be used in
 * advertising or publicity pertaining to distribution of the software without
 * specific, written prior permission. Copyright holders make no
 * representations about the suitability of this software for any purpose.  It
 * is provided "as is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
 * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

/** @file
 * This is the header containing the public API of EXA for exa drivers.
 */

#ifndef EXA_H
#define EXA_H

#include "scrnintstr.h"
#include "pixmapstr.h"
#include "windowstr.h"
#include "gcstruct.h"
#include "picturestr.h"
#include "fb.h"

#define EXA_VERSION_MAJOR   2
#define EXA_VERSION_MINOR   2
#define EXA_VERSION_RELEASE 0

typedef struct _ExaOffscreenArea ExaOffscreenArea;

typedef void (*ExaOffscreenSaveProc) (ScreenPtr pScreen, ExaOffscreenArea *area);

typedef enum _ExaOffscreenState {
    ExaOffscreenAvail,
    ExaOffscreenRemovable,
    ExaOffscreenLocked
} ExaOffscreenState;

struct _ExaOffscreenArea {
    int                 base_offset;    /* allocation base */
    int                 offset;         /* aligned offset */
    int                 size;           /* total allocation size */
    int                 score;
    pointer             privData;

    ExaOffscreenSaveProc save;

    ExaOffscreenState   state;

    ExaOffscreenArea    *next;
};

/**
 * The ExaDriver structure is allocated through exaDriverAlloc(), and then
 * fllled in by drivers.
 */
typedef struct _ExaDriver {
    /**
     * exa_major and exa_minor should be set by the driver to the version of
     * EXA which the driver was compiled for (or configures itself at runtime
     * to support).  This allows EXA to extend the structure for new features
     * without breaking ABI for drivers compiled against older versions.
     */
    int exa_major, exa_minor;

    /**
     * memoryBase is the address of the beginning of framebuffer memory.
     * The visible screen should be within memoryBase to memoryBase +
     * memorySize.
     */
    CARD8         *memoryBase;

    /**
     * offScreenBase is the offset from memoryBase of the beginning of the area
     * to be managed by EXA's linear offscreen memory manager.
     *
     * In XFree86 DDX drivers, this is probably:
     *   (pScrn->displayWidth * cpp * pScrn->virtualY)
     */
    unsigned long  offScreenBase;

    /**
     * memorySize is the length (in bytes) of framebuffer memory beginning
     * from memoryBase.
     *
     * The offscreen memory manager will manage the area beginning at
     * (memoryBase + offScreenBase), with a length of (memorySize -
     * offScreenBase)
     *
     * In XFree86 DDX drivers, this is probably (pScrn->videoRam * 1024)
     */
    unsigned long memorySize;

    /**
     * pixmapOffsetAlign is the byte alignment necessary for pixmap offsets
     * within framebuffer.
     *
     * Hardware typically has a required alignment of offsets, which may or may
     * not be a power of two.  EXA will ensure that pixmaps managed by the
     * offscreen memory manager meet this alignment requirement.
     */
    int pixmapOffsetAlign;

    /**
     * pixmapPitchAlign is the byte alignment necessary for pixmap pitches
     * within the framebuffer.
     *
     * Hardware typically has a required alignment of pitches for acceleration.
     * For 3D hardware, Composite acceleration often requires that source and
     * mask pixmaps (textures) have a power-of-two pitch, which can be demanded
     * using EXA_OFFSCREEN_ALIGN_POT.  These pitch requirements only apply to
     * pixmaps managed by the offscreen memory manager.  Thus, it is up to the
     * driver to ensure that the visible screen has an appropriate pitch for
     * acceleration.
     */
    int pixmapPitchAlign;

    /**
     * The flags field is bitfield of boolean values controlling EXA's behavior.
     *
     * The flags in clude EXA_OFFSCREEN_PIXMAPS, EXA_OFFSCREEN_ALIGN_POT, and
     * EXA_TWO_BITBLT_DIRECTIONS.
     */
    int flags;

    /** @{ */
    /**
     * maxX controls the X coordinate limitation for rendering from the card.
     * The driver should never receive a request for rendering beyond maxX
     * in the X direction from the origin of a pixmap.
     */
    int maxX;

    /**
     * maxY controls the Y coordinate limitation for rendering from the card.
     * The driver should never receive a request for rendering beyond maxY
     * in the Y direction from the origin of a pixmap.
     */
    int maxY;
    /** @} */

    /* private */
    ExaOffscreenArea *offScreenAreas;
    Bool              needsSync;
    int               lastMarker;

    /** @name Solid
     * @{
     */
    /**
     * PrepareSolid() sets up the driver for doing a solid fill.
     * @param pPixmap Destination pixmap
     * @param alu raster operation
     * @param planemask write mask for the fill
     * @param fg "foreground" color for the fill
     *
     * This call should set up the driver for doing a series of solid fills
     * through the Solid() call.  The alu raster op is one of the GX*
     * graphics functions listed in X.h, and typically maps to a similar
     * single-byte "ROP" setting in all hardware.  The planemask controls
     * which bits of the destination should be affected, and will only represent
     * the bits up to the depth of pPixmap.  The fg is the pixel value of the
     * foreground color referred to in ROP descriptions.
     *
     * Note that many drivers will need to store some of the data in the driver
     * private record, for sending to the hardware with each drawing command.
     *
     * The PrepareSolid() call is required of all drivers, but it may fail for any
     * reason.  Failure results in a fallback to software rendering.
     */
    Bool        (*PrepareSolid) (PixmapPtr      pPixmap,
                                 int            alu,
                                 Pixel          planemask,
                                 Pixel          fg);

    /**
     * Solid() performs a solid fill set up in the last PrepareSolid() call.
     *
     * @param pPixmap destination pixmap
     * @param x1 left coordinate
     * @param y1 top coordinate
     * @param x2 right coordinate
     * @param y2 bottom coordinate
     *
     * Performs the fill set up by the last PrepareSolid() call, covering the
     * area from (x1,y1) to (x2,y2) in pPixmap.  Note that the coordinates are
     * in the coordinate space of the destination pixmap, so the driver will
     * need to set up the hardware's offset and pitch for the destination
     * coordinates according to the pixmap's offset and pitch within
     * framebuffer.  This likely means using exaGetPixmapOffset() and
     * exaGetPixmapPitch().
     *
     * This call is required if PrepareSolid() ever succeeds.
     */
    void        (*Solid) (PixmapPtr      pPixmap, int x1, int y1, int x2, int y2);

    /**
     * DoneSolid() finishes a set of solid fills.
     *
     * @param pPixmap destination pixmap.
     *
     * The DoneSolid() call is called at the end of a series of consecutive
     * Solid() calls following a successful PrepareSolid().  This allows drivers
     * to finish up emitting drawing commands that were buffered, or clean up
     * state from PrepareSolid().
     *
     * This call is required if PrepareSolid() ever succeeds.
     */
    void        (*DoneSolid) (PixmapPtr      pPixmap);
    /** @} */

    /** @name Copy
     * @{
     */
    /**
     * PrepareCopy() sets up the driver for doing a copy within video 
     * memory.
     *
     * @param pSrcPixmap source pixmap
     * @param pDstPixmap destination pixmap
     * @param dx X copy direction
     * @param dy Y copy direction
     * @param alu raster operation
     * @param planemask write mask for the fill
     *
     * This call should set up the driver for doing a series of copies from the
     * the pSrcPixmap to the pDstPixmap.  The dx flag will be positive if the
     * hardware should do the copy from the left to the right, and dy will be
     * positive if the copy should be done from the top to the bottom.  This
     * is to deal with self-overlapping copies when pSrcPixmap == pDstPixmap.
     * If your hardware can only support blits that are (left to right, top to
     * bottom) or (right to left, bottom to top), then you should set
     * #EXA_TWO_BITBLT_DIRECTIONS, and EXA will break down Copy operations to
     * ones that meet those requirements.  The alu raster op is one of the GX*
     * graphics functions listed in X.h, and typically maps to a similar
     * single-byte "ROP" setting in all hardware.  The planemask controls which
     * bits of the destination should be affected, and will only represent the
     * bits up to the depth of pPixmap.
     *
     * Note that many drivers will need to store some of the data in the driver
     * private record, for sending to the hardware with each drawing command.
     *
     * The PrepareCopy() call is required of all drivers, but it may fail for any
     * reason.  Failure results in a fallback to software rendering.
     */
    Bool        (*PrepareCopy) (PixmapPtr       pSrcPixmap,
                                PixmapPtr       pDstPixmap,
                                int             dx,
                                int             dy,
                                int             alu,
                                Pixel           planemask);

    /**
     * Copy() performs a copy set up in the last PrepareCopy call.
     *
     * @param pDstPixmap destination pixmap
     * @param srcX source X coordinate
     * @param srcY source Y coordinate
     * @param dstX destination X coordinate
     * @param dstY destination Y coordinate
     * @param width width of the rectangle to be copied
     * @param height height of the rectangle to be copied.
     *
     * Performs the copy set up by the last PrepareCopy() call, copying the
     * rectangle from (srcX, srcY) to (srcX + width, srcY + width) in the source
     * pixmap to the same-sized rectangle at (dstX, dstY) in the destination
     * pixmap.  Those rectangles may overlap in memory, if
     * pSrcPixmap == pDstPixmap.  Note that this call does not receive the
     * pSrcPixmap as an argument -- if it's needed in this function, it should
     * be stored in the driver private during PrepareCopy().  As with Solid(),
     * the coordinates are in the coordinate space of each pixmap, so the driver
     * will need to set up source and destination pitches and offsets from those
     * pixmaps, probably using exaGetPixmapOffset() and exaGetPixmapPitch().
     *
     * This call is required if PrepareCopy ever succeeds.
     */
    void        (*Copy) (PixmapPtr       pDstPixmap,
                         int    srcX,
                         int    srcY,
                         int    dstX,
                         int    dstY,
                         int    width,
                         int    height);

    /**
     * DoneCopy() finishes a set of copies.
     *
     * @param pPixmap destination pixmap.
     *
     * The DoneCopy() call is called at the end of a series of consecutive
     * Copy() calls following a successful PrepareCopy().  This allows drivers
     * to finish up emitting drawing commands that were buffered, or clean up
     * state from PrepareCopy().
     *
     * This call is required if PrepareCopy() ever succeeds.
     */
    void        (*DoneCopy) (PixmapPtr       pDstPixmap);
    /** @} */

    /** @name Composite
     * @{
     */
    /**
     * CheckComposite() checks to see if a composite operation could be
     * accelerated.
     *
     * @param op Render operation
     * @param pSrcPicture source Picture
     * @param pMaskPicture mask picture
     * @param pDstPicture destination Picture
     *
     * The CheckComposite() call checks if the driver could handle acceleration
     * of op with the given source, mask, and destination pictures.  This allows
     * drivers to check source and destination formats, supported operations,
     * transformations, and component alpha state, and send operations it can't
     * support to software rendering early on.  This avoids costly pixmap
     * migration to the wrong places when the driver can't accelerate
     * operations.  Note that because migration hasn't happened, the driver
     * can't know during CheckComposite() what the offsets and pitches of the
     * pixmaps are going to be.
     *
     * See PrepareComposite() for more details on likely issues that drivers
     * will have in accelerating Composite operations.
     *
     * The CheckComposite() call is recommended if PrepareComposite() is
     * implemented, but is not required.
     */
    Bool        (*CheckComposite) (int          op,
                                   PicturePtr   pSrcPicture,
                                   PicturePtr   pMaskPicture,
                                   PicturePtr   pDstPicture);

    /**
     * PrepareComposite() sets up the driver for doing a Composite operation
     * described in the Render extension protocol spec.
     *
     * @param op Render operation
     * @param pSrcPicture source Picture
     * @param pMaskPicture mask picture
     * @param pDstPicture destination Picture
     * @param pSrc source pixmap
     * @param pMask mask pixmap
     * @param pDst destination pixmap
     *
     * This call should set up the driver for doing a series of Composite
     * operations, as described in the Render protocol spec, with the given
     * pSrcPicture, pMaskPicture, and pDstPicture.  The pSrc, pMask, and
     * pDst are the pixmaps containing the pixel data, and should be used for
     * setting the offset and pitch used for the coordinate spaces for each of
     * the Pictures.
     *
     * Notes on interpreting Picture structures:
     * - The Picture structures will always have a valid pDrawable.
     * - The Picture structures will never have alphaMap set.
     * - The mask Picture (and therefore pMask) may be NULL, in which case the
     *   operation is simply src OP dst instead of src IN mask OP dst, and
     *   mask coordinates should be ignored.
     * - pMarkPicture may have componentAlpha set, which greatly changes
     *   the behavior of the Composite operation.  componentAlpha has no effect
     *   when set on pSrcPicture or pDstPicture.
     * - The source and mask Pictures may have a transformation set
     *   (Picture->transform != NULL), which means that the source coordinates
     *   should be transformed by that transformation, resulting in scaling,
     *   rotation, etc.  The PictureTransformPoint() call can transform
     *   coordinates for you.  Transforms have no effect on Pictures when used
     *   as a destination.
     * - The source and mask pictures may have a filter set.  PictFilterNearest
     *   and PictFilterBilinear are defined in the Render protocol, but others
     *   may be encountered, and must be handled correctly (usually by
     *   PrepareComposite failing, and falling back to software).  Filters have
     *   no effect on Pictures when used as a destination.
     * - The source and mask Pictures may have repeating set, which must be
     *   respected.  Many chipsets will be unable to support repeating on
     *   pixmaps that have a width or height that is not a power of two.
     *
     * If your hardware can't support source pictures (textures) with
     * non-power-of-two pitches, you should set #EXA_OFFSCREEN_ALIGN_POT.
     *
     * Note that many drivers will need to store some of the data in the driver
     * private record, for sending to the hardware with each drawing command.
     *
     * The PrepareComposite() call is not required.  However, it is highly
     * recommended for performance of antialiased font rendering and performance
     * of cairo applications.  Failure results in a fallback to software
     * rendering.
     */
    Bool        (*PrepareComposite) (int                op,
                                     PicturePtr         pSrcPicture,
                                     PicturePtr         pMaskPicture,
                                     PicturePtr         pDstPicture,
                                     PixmapPtr          pSrc,
                                     PixmapPtr          pMask,
                                     PixmapPtr          pDst);

    /**
     * Composite() performs a Composite operation set up in the last
     * PrepareComposite() call.
     *
     * @param pDstPixmap destination pixmap
     * @param srcX source X coordinate
     * @param srcY source Y coordinate
     * @param maskX source X coordinate
     * @param maskY source Y coordinate
     * @param dstX destination X coordinate
     * @param dstY destination Y coordinate
     * @param width destination rectangle width
     * @param height destination rectangle height
     *
     * Performs the Composite operation set up by the last PrepareComposite()
     * call, to the rectangle from (dstX, dstY) to (dstX + width, dstY + height)
     * in the destination Pixmap.  Note that if a transformation was set on
     * the source or mask Pictures, the source rectangles may not be the same
     * size as the destination rectangles and filtering.  Getting the coordinate
     * transformation right at the subpixel level can be tricky, and rendercheck
     * can test this for you.
     *
     * This call is required if PrepareComposite() ever succeeds.
     */
    void        (*Composite) (PixmapPtr         pDst,
                              int       srcX,
                              int        srcY,
                              int        maskX,
                              int        maskY,
                              int        dstX,
                              int        dstY,
                              int        width,
                              int        height);

    /**
     * DoneComposite() finishes a set of Composite operations.
     *
     * @param pPixmap destination pixmap.
     *
     * The DoneComposite() call is called at the end of a series of consecutive
     * Composite() calls following a successful PrepareComposite().  This allows
     * drivers to finish up emitting drawing commands that were buffered, or
     * clean up state from PrepareComposite().
     *
     * This call is required if PrepareComposite() ever succeeds.
     */
    void        (*DoneComposite) (PixmapPtr         pDst);
    /** @} */

    /**
     * UploadToScreen() loads a rectangle of data from src into pDst.
     *
     * @param pDst destination pixmap
     * @param x destination X coordinate.
     * @param y destination Y coordinate
     * @param width width of the rectangle to be copied
     * @param height height of the rectangle to be copied
     * @param src pointer to the beginning of the source data
     * @param src_pitch pitch (in bytes) of the lines of source data.
     *
     * UploadToScreen() copies data in system memory beginning at src (with
     * pitch src_pitch) into the destination pixmap from (x, y) to
     * (x + width, y + height).  This is typically done with hostdata uploads,
     * where the CPU sets up a blit command on the hardware with instructions
     * that the blit data will be fed through some sort of aperture on the card.
     *
     * If UploadToScreen() is performed asynchronously, it is up to the driver
     * to call exaMarkSync().  This is in contrast to most other acceleration
     * calls in EXA.
     *
     * UploadToScreen() can aid in pixmap migration, but is most important for
     * the performance of exaGlyphs() (antialiased font drawing) by allowing
     * pipelining of data uploads, avoiding a sync of the card after each glyph.
     * 
     * @return TRUE if the driver successfully uploaded the data.  FALSE
     * indicates that EXA should fall back to doing the upload in software.
     *
     * UploadToScreen() is not required, but is recommended if Composite
     * acceleration is supported.
     */
    Bool        (*UploadToScreen) (PixmapPtr            pDst,
                                   int                  x,
                                   int                  y,
                                   int                  w,
                                   int                  h,
                                   char                 *src,
                                   int                  src_pitch);

    /**
     * UploadToScratch() is used to upload a pixmap to a scratch area for
     * acceleration.
     *
     * @param pSrc source pixmap in host memory
     * @param pDst fake, scratch pixmap to be set up in offscreen memory.
     *
     * The UploadToScratch() call was added to support Xati before Xati had
     * support for hostdata uploads and before exaGlyphs() was written.  It
     * behaves incorrectly (uses an invalid pixmap as pDst),
     * and UploadToScreen() should be implemented instead.
     *
     * Drivers implementing UploadToScratch() had to set up space (likely in a
     * statically allocated area) in offscreen memory, copy pSrc to that
     * scratch area, and adust pDst->devKind for the pitch and
     * pDst->devPrivate.ptr for the pointer to that scratch area.  The driver
     * was responsible for syncing (as it was implemented using memcpy() in
     * Xati), and only the data from the last UploadToScratch() was guaranteed
     * to be valid at any given time.
     *
     * UploadToScratch() should not be implemented by drivers, and will likely
     * be removed in a future version of EXA.
     */
    Bool        (*UploadToScratch) (PixmapPtr           pSrc,
                                    PixmapPtr           pDst);

    /**
     * DownloadFromScreen() loads a rectangle of data from pSrc into dst
     *
     * @param pSrc source pixmap
     * @param x source X coordinate.
     * @param y source Y coordinate
     * @param width width of the rectangle to be copied
     * @param height height of the rectangle to be copied
     * @param dst pointer to the beginning of the destination data
     * @param dst_pitch pitch (in bytes) of the lines of destination data.
     *
     * DownloadFromScreen() copies data from offscreen memory in pSrc from
     * (x, y) to (x + width, y + height), to system memory starting at
     * dst (with pitch dst_pitch).  This would usually be done
     * using scatter-gather DMA, supported by a DRM call, or by blitting to AGP
     * and then synchronously reading from AGP.  Because the implementation
     * might be synchronous, EXA leaves it up to the driver to call
     * exaMarkSync() if DownloadFromScreen() was asynchronous.  This is in
     * contrast to most other acceleration calls in EXA.
     *
     * DownloadFromScreen() can aid in the largest bottleneck in pixmap
     * migration, which is the read from framebuffer when evicting pixmaps from
     * framebuffer memory.  Thus, it is highly recommended, even though
     * implementations are typically complicated.
     * 
     * @return TRUE if the driver successfully downloaded the data.  FALSE
     * indicates that EXA should fall back to doing the download in software.
     *
     * DownloadFromScreen() is not required, but is highly recommended.
     */
    Bool (*DownloadFromScreen)(PixmapPtr pSrc,
                               int x,  int y,
                               int w,  int h,
                               char *dst,  int dst_pitch);

    /**
     * MarkSync() requests that the driver mark a synchronization point,
     * returning an driver-defined integer marker which could be requested for
     * synchronization to later in WaitMarker().  This might be used in the
     * future to avoid waiting for full hardware stalls before accessing pixmap
     * data with the CPU, but is not important in the current incarnation of
     * EXA.
     *
     * Note that drivers should call exaMarkSync() when they have done some
     * acceleration, rather than their own MarkSync() handler, as otherwise EXA
     * will be unaware of the driver's acceleration and not sync to it during
     * fallbacks.
     *
     * MarkSync() is optional.
     */
    int         (*MarkSync)   (ScreenPtr pScreen);

    /**
     * WaitMarker() waits for all rendering before the given marker to have
     * completed.  If the driver does not implement MarkSync(), marker is
     * meaningless, and all rendering by the hardware should be completed before
     * WaitMarker() returns.
     *
     * Note that drivers should call exaWaitSync() to wait for all acceleration
     * to finish, as otherwise EXA will be unaware of the driver having
     * synchronized, resulting in excessive WaitMarker() calls.
     *
     * WaitMarker() is required of all drivers.
     */
    void        (*WaitMarker) (ScreenPtr pScreen, int marker);

    /** @{ */
    /**
     * PrepareAccess() is called before CPU access to an offscreen pixmap.
     *
     * @param pPix the pixmap being accessed
     * @param index the index of the pixmap being accessed.
     *
     * PrepareAccess() will be called before CPU access to an offscreen pixmap.
     * This can be used to set up hardware surfaces for byteswapping or
     * untiling, or to adjust the pixmap's devPrivate.ptr for the purpose of
     * making CPU access use a different aperture.
     *
     * The index is one of #EXA_PREPARE_DEST, #EXA_PREPARE_SRC, or
     * #EXA_PREPARE_MASK, indicating which pixmap is in question.  Since only up
     * to three pixmaps will have PrepareAccess() called on them per operation,
     * drivers can have a small, statically-allocated space to maintain state
     * for PrepareAccess() and FinishAccess() in.  Note that the same pixmap may
     * have PrepareAccess() called on it more than once, for example when doing
     * a copy within the same pixmap (so it gets PrepareAccess as()
     * #EXA_PREPARE_DEST and then as #EXA_PREPARE_SRC).
     *
     * PrepareAccess() may fail.  An example might be the case of hardware that
     * can set up 1 or 2 surfaces for CPU access, but not 3.  If PrepareAccess()
     * fails, EXA will migrate the pixmap to system memory.
     * DownloadFromScreen() must be implemented and must not fail if a driver
     * wishes to fail in PrepareAccess().  PrepareAccess() must not fail when
     * pPix is the visible screen, because the visible screen can not be
     * migrated.
     *
     * @return TRUE if PrepareAccess() successfully prepared the pixmap for CPU
     * drawing.
     * @return FALSE if PrepareAccess() is unsuccessful and EXA should use
     * DownloadFromScreen() to migate the pixmap out.
     */
    Bool        (*PrepareAccess)(PixmapPtr pPix, int index);

    /**
     * FinishAccess() is called after CPU access to an offscreen pixmap.
     *
     * @param pPix the pixmap being accessed
     * @param index the index of the pixmap being accessed.
     *
     * FinishAccess() will be called after finishing CPU access of an offscreen
     * pixmap set up by PrepareAccess().  Note that the FinishAccess() will not be
     * called if PrepareAccess() failed and the pixmap was migrated out.
     */
    void        (*FinishAccess)(PixmapPtr pPix, int index);

    /**
     * PixmapIsOffscreen() is an optional driver replacement to
     * exaPixmapIsOffscreen(). Set to NULL if you want the standard behaviour
     * of exaPixmapIsOffscreen().
     *
     * @param pPix the pixmap
     * @return TRUE if the given drawable is in framebuffer memory.
     *
     * exaPixmapIsOffscreen() is used to determine if a pixmap is in offscreen
     * memory, meaning that acceleration could probably be done to it, and that it
     * will need to be wrapped by PrepareAccess()/FinishAccess() when accessing it
     * with the CPU.
     *
     *
     */
    Bool        (*PixmapIsOffscreen)(PixmapPtr pPix);

        /** @name PrepareAccess() and FinishAccess() indices
         * @{
         */
        /**
         * EXA_PREPARE_DEST is the index for a pixmap that may be drawn to or
         * read from.
         */ 
        #define EXA_PREPARE_DEST        0
        /**
         * EXA_PREPARE_SRC is the index for a pixmap that may be read from
         */
        #define EXA_PREPARE_SRC         1
        /**
         * EXA_PREPARE_SRC is the index for a second pixmap that may be read
         * from.
         */
        #define EXA_PREPARE_MASK        2
        /** @} */
    /** @} */
} ExaDriverRec, *ExaDriverPtr;

/** @name EXA driver flags
 * @{
 */
/**
 * EXA_OFFSCREEN_PIXMAPS indicates to EXA that the driver can support 
 * offscreen pixmaps.
 */
#define EXA_OFFSCREEN_PIXMAPS           (1 << 0)

/**
 * EXA_OFFSCREEN_ALIGN_POT indicates to EXA that the driver needs pixmaps
 * to have a power-of-two pitch.
 */
#define EXA_OFFSCREEN_ALIGN_POT         (1 << 1)

/**
 * EXA_TWO_BITBLT_DIRECTIONS indicates to EXA that the driver can only
 * support copies that are (left-to-right, top-to-bottom) or
 * (right-to-left, bottom-to-top).
 */
#define EXA_TWO_BITBLT_DIRECTIONS       (1 << 2)
/** @} */

ExaDriverPtr
exaDriverAlloc(void);

Bool
exaDriverInit(ScreenPtr                pScreen,
              ExaDriverPtr   pScreenInfo);

void
exaDriverFini(ScreenPtr                pScreen);

void
exaMarkSync(ScreenPtr pScreen);
void
exaWaitSync(ScreenPtr pScreen);

ExaOffscreenArea *
exaOffscreenAlloc(ScreenPtr pScreen, int size, int align,
                  Bool locked,
                  ExaOffscreenSaveProc save,
                  pointer privData);

ExaOffscreenArea *
exaOffscreenFree(ScreenPtr pScreen, ExaOffscreenArea *area);

void
ExaOffscreenMarkUsed (PixmapPtr pPixmap);

unsigned long
exaGetPixmapOffset(PixmapPtr pPix);

unsigned long
exaGetPixmapPitch(PixmapPtr pPix);

unsigned long
exaGetPixmapSize(PixmapPtr pPix);

void
exaEnableDisableFBAccess (int index, Bool enable);

void
exaMoveInPixmap (PixmapPtr pPixmap);

void
exaMoveOutPixmap (PixmapPtr pPixmap);

/**
 * Returns TRUE if the given planemask covers all the significant bits in the
 * pixel values for pDrawable.
 */
#define EXA_PM_IS_SOLID(_pDrawable, _pm) \
        (((_pm) & FbFullMask((_pDrawable)->depth)) == \
         FbFullMask((_pDrawable)->depth))

#endif /* EXA_H */