3 * DRI utility functions.
5 * This module acts as glue between GLX and the actual hardware driver. A DRI
6 * driver doesn't really \e have to use any of this - it's optional. But, some
7 * useful stuff is done here that otherwise would have to be duplicated in most
10 * Basically, these utility functions take care of some of the dirty details of
11 * screen initialization, context creation, context binding, DRM setup, etc.
13 * These functions are compiled into each DRI driver so libGL.so knows nothing
25 #define MAP_FAILED ((void *)-1)
28 #include "main/imports.h"
32 #include "drm_sarea.h"
35 #include "../glsl/glsl_parser_extras.h"
37 PUBLIC const char __dri2ConfigOptions[] =
39 DRI_CONF_SECTION_PERFORMANCE
40 DRI_CONF_VBLANK_MODE(DRI_CONF_VBLANK_DEF_INTERVAL_1)
44 static const uint __dri2NConfigOptions = 1;
46 #ifndef GLX_OML_sync_control
47 typedef GLboolean ( * PFNGLXGETMSCRATEOMLPROC) (__DRIdrawable *drawable, int32_t *numerator, int32_t *denominator);
50 static void dri_get_drawable(__DRIdrawable *pdp);
51 static void dri_put_drawable(__DRIdrawable *pdp);
54 * This is just a token extension used to signal that the driver
55 * supports setting a read drawable.
57 const __DRIextension driReadDrawableExtension = {
58 __DRI_READ_DRAWABLE, __DRI_READ_DRAWABLE_VERSION
62 driIntersectArea( drm_clip_rect_t rect1, drm_clip_rect_t rect2 )
64 if (rect2.x1 > rect1.x1) rect1.x1 = rect2.x1;
65 if (rect2.x2 < rect1.x2) rect1.x2 = rect2.x2;
66 if (rect2.y1 > rect1.y1) rect1.y1 = rect2.y1;
67 if (rect2.y2 < rect1.y2) rect1.y2 = rect2.y2;
69 if (rect1.x1 > rect1.x2 || rect1.y1 > rect1.y2) return 0;
71 return (rect1.x2 - rect1.x1) * (rect1.y2 - rect1.y1);
74 /*****************************************************************/
75 /** \name Context (un)binding functions */
76 /*****************************************************************/
82 * \param scrn the screen.
85 * \return \c GL_TRUE on success, or \c GL_FALSE on failure.
88 * This function calls __DriverAPIRec::UnbindContext, and then decrements
89 * __DRIdrawableRec::refcount which must be non-zero for a successful
92 * While casting the opaque private pointers associated with the parameters
93 * into their respective real types it also assures they are not \c NULL.
95 static int driUnbindContext(__DRIcontext *pcp)
102 ** Assume error checking is done properly in glXMakeCurrent before
103 ** calling driUnbindContext.
109 psp = pcp->driScreenPriv;
110 pdp = pcp->driDrawablePriv;
111 prp = pcp->driReadablePriv;
113 /* already unbound */
116 /* Let driver unbind drawable from context */
117 (*psp->DriverAPI.UnbindContext)(pcp);
120 if (pdp->refcount == 0) {
125 dri_put_drawable(pdp);
128 if (prp->refcount == 0) {
133 dri_put_drawable(prp);
137 /* XXX this is disabled so that if we call SwapBuffers on an unbound
138 * window we can determine the last context bound to the window and
139 * use that context's lock. (BrianP, 2-Dec-2000)
141 pcp->driDrawablePriv = pcp->driReadablePriv = NULL;
147 * This function takes both a read buffer and a draw buffer. This is needed
148 * for \c glXMakeCurrentReadSGI or GLX 1.3's \c glXMakeContextCurrent
151 static int driBindContext(__DRIcontext *pcp,
155 __DRIscreen *psp = NULL;
158 ** Assume error checking is done properly in glXMakeCurrent before
159 ** calling driUnbindContext.
165 /* Bind the drawable to the context */
166 psp = pcp->driScreenPriv;
167 pcp->driDrawablePriv = pdp;
168 pcp->driReadablePriv = prp;
170 pdp->driContextPriv = pcp;
171 dri_get_drawable(pdp);
173 if (prp && pdp != prp) {
174 dri_get_drawable(prp);
178 ** Now that we have a context associated with this drawable, we can
179 ** initialize the drawable information if has not been done before.
182 if (!psp->dri2.enabled) {
183 if (pdp && !pdp->pStamp) {
184 DRM_SPINLOCK(&psp->pSAREA->drawable_lock, psp->drawLockID);
185 __driUtilUpdateDrawableInfo(pdp);
186 DRM_SPINUNLOCK(&psp->pSAREA->drawable_lock, psp->drawLockID);
188 if (prp && pdp != prp && !prp->pStamp) {
189 DRM_SPINLOCK(&psp->pSAREA->drawable_lock, psp->drawLockID);
190 __driUtilUpdateDrawableInfo(prp);
191 DRM_SPINUNLOCK(&psp->pSAREA->drawable_lock, psp->drawLockID);
195 /* Call device-specific MakeCurrent */
196 return (*psp->DriverAPI.MakeCurrent)(pcp, pdp, prp);
202 /*****************************************************************/
203 /** \name Drawable handling functions */
204 /*****************************************************************/
208 * Update private drawable information.
210 * \param pdp pointer to the private drawable information to update.
212 * This function basically updates the __DRIdrawable struct's
213 * cliprect information by calling \c __DRIinterfaceMethods::getDrawableInfo.
214 * This is usually called by the DRI_VALIDATE_DRAWABLE_INFO macro which
215 * compares the __DRIdrwablePrivate pStamp and lastStamp values. If
216 * the values are different that means we have to update the clipping
220 __driUtilUpdateDrawableInfo(__DRIdrawable *pdp)
222 __DRIscreen *psp = pdp->driScreenPriv;
223 __DRIcontext *pcp = pdp->driContextPriv;
226 || ((pdp != pcp->driDrawablePriv) && (pdp != pcp->driReadablePriv))) {
228 * ...but we must ignore it. There can be many contexts bound to a
233 if (pdp->pClipRects) {
234 free(pdp->pClipRects);
235 pdp->pClipRects = NULL;
238 if (pdp->pBackClipRects) {
239 free(pdp->pBackClipRects);
240 pdp->pBackClipRects = NULL;
243 DRM_SPINUNLOCK(&psp->pSAREA->drawable_lock, psp->drawLockID);
245 if (! (*psp->getDrawableInfo->getDrawableInfo)(pdp,
246 &pdp->index, &pdp->lastStamp,
247 &pdp->x, &pdp->y, &pdp->w, &pdp->h,
248 &pdp->numClipRects, &pdp->pClipRects,
251 &pdp->numBackClipRects,
252 &pdp->pBackClipRects,
253 pdp->loaderPrivate)) {
254 /* Error -- eg the window may have been destroyed. Keep going
257 pdp->pStamp = &pdp->lastStamp; /* prevent endless loop */
258 pdp->numClipRects = 0;
259 pdp->pClipRects = NULL;
260 pdp->numBackClipRects = 0;
261 pdp->pBackClipRects = NULL;
264 pdp->pStamp = &(psp->pSAREA->drawableTable[pdp->index].stamp);
266 DRM_SPINLOCK(&psp->pSAREA->drawable_lock, psp->drawLockID);
271 /*****************************************************************/
272 /** \name GLX callbacks */
273 /*****************************************************************/
276 static void driReportDamage(__DRIdrawable *pdp,
277 struct drm_clip_rect *pClipRects, int numClipRects)
279 __DRIscreen *psp = pdp->driScreenPriv;
281 /* Check that we actually have the new damage report method */
283 /* Report the damage. Currently, all our drivers draw
284 * directly to the front buffer, so we report the damage there
285 * rather than to the backing storein (if any).
287 (*psp->damage->reportDamage)(pdp,
289 pClipRects, numClipRects,
290 GL_TRUE, pdp->loaderPrivate);
298 * \param drawablePrivate opaque pointer to the per-drawable private info.
301 * This function calls __DRIdrawable::swapBuffers.
303 * Is called directly from glXSwapBuffers().
305 static void driSwapBuffers(__DRIdrawable *dPriv)
307 __DRIscreen *psp = dPriv->driScreenPriv;
308 drm_clip_rect_t *rects;
311 psp->DriverAPI.SwapBuffers(dPriv);
313 if (!dPriv->numClipRects)
316 rects = malloc(sizeof(*rects) * dPriv->numClipRects);
321 for (i = 0; i < dPriv->numClipRects; i++) {
322 rects[i].x1 = dPriv->pClipRects[i].x1 - dPriv->x;
323 rects[i].y1 = dPriv->pClipRects[i].y1 - dPriv->y;
324 rects[i].x2 = dPriv->pClipRects[i].x2 - dPriv->x;
325 rects[i].y2 = dPriv->pClipRects[i].y2 - dPriv->y;
328 driReportDamage(dPriv, rects, dPriv->numClipRects);
332 static int driDrawableGetMSC( __DRIscreen *sPriv, __DRIdrawable *dPriv,
335 return sPriv->DriverAPI.GetDrawableMSC(sPriv, dPriv, msc);
339 static int driWaitForMSC(__DRIdrawable *dPriv, int64_t target_msc,
340 int64_t divisor, int64_t remainder,
341 int64_t * msc, int64_t * sbc)
346 status = dPriv->driScreenPriv->DriverAPI.WaitForMSC( dPriv, target_msc,
350 /* GetSwapInfo() may not be provided by the driver if GLX_SGI_video_sync
351 * is supported but GLX_OML_sync_control is not. Therefore, don't return
352 * an error value if GetSwapInfo() is not implemented.
355 && dPriv->driScreenPriv->DriverAPI.GetSwapInfo ) {
356 status = dPriv->driScreenPriv->DriverAPI.GetSwapInfo( dPriv, & sInfo );
357 *sbc = sInfo.swap_count;
364 const __DRImediaStreamCounterExtension driMediaStreamCounterExtension = {
365 { __DRI_MEDIA_STREAM_COUNTER, __DRI_MEDIA_STREAM_COUNTER_VERSION },
371 static void driCopySubBuffer(__DRIdrawable *dPriv,
372 int x, int y, int w, int h)
374 drm_clip_rect_t rect;
377 rect.y1 = dPriv->h - y - h;
379 rect.y2 = rect.y1 + h;
380 driReportDamage(dPriv, &rect, 1);
382 dPriv->driScreenPriv->DriverAPI.CopySubBuffer(dPriv, x, y, w, h);
385 const __DRIcopySubBufferExtension driCopySubBufferExtension = {
386 { __DRI_COPY_SUB_BUFFER, __DRI_COPY_SUB_BUFFER_VERSION },
390 static void driSetSwapInterval(__DRIdrawable *dPriv, unsigned int interval)
392 dPriv->swap_interval = interval;
395 static unsigned int driGetSwapInterval(__DRIdrawable *dPriv)
397 return dPriv->swap_interval;
400 const __DRIswapControlExtension driSwapControlExtension = {
401 { __DRI_SWAP_CONTROL, __DRI_SWAP_CONTROL_VERSION },
408 * This is called via __DRIscreenRec's createNewDrawable pointer.
410 static __DRIdrawable *
411 driCreateNewDrawable(__DRIscreen *psp, const __DRIconfig *config,
412 drm_drawable_t hwDrawable, int renderType,
413 const int *attrs, void *data)
417 /* Since pbuffers are not yet supported, no drawable attributes are
422 pdp = malloc(sizeof *pdp);
427 pdp->driContextPriv = NULL;
428 pdp->loaderPrivate = data;
429 pdp->hHWDrawable = hwDrawable;
438 pdp->numClipRects = 0;
439 pdp->numBackClipRects = 0;
440 pdp->pClipRects = NULL;
441 pdp->pBackClipRects = NULL;
445 pdp->driScreenPriv = psp;
447 if (!(*psp->DriverAPI.CreateBuffer)(psp, pdp, &config->modes, 0)) {
454 /* This special default value is replaced with the configured
455 * default value when the drawable is first bound to a direct
458 pdp->swap_interval = (unsigned)-1;
464 static __DRIdrawable *
465 dri2CreateNewDrawable(__DRIscreen *screen,
466 const __DRIconfig *config,
469 __DRIdrawable *pdraw;
471 pdraw = driCreateNewDrawable(screen, config, 0, 0, NULL, loaderPrivate);
475 pdraw->pClipRects = &pdraw->dri2.clipRect;
476 pdraw->pBackClipRects = &pdraw->dri2.clipRect;
478 pdraw->pStamp = &pdraw->dri2.stamp;
479 *pdraw->pStamp = pdraw->lastStamp + 1;
485 dri2ConfigQueryb(__DRIscreen *screen, const char *var, GLboolean *val)
487 if (!driCheckOption(&screen->optionCache, var, DRI_BOOL))
490 *val = driQueryOptionb(&screen->optionCache, var);
496 dri2ConfigQueryi(__DRIscreen *screen, const char *var, GLint *val)
498 if (!driCheckOption(&screen->optionCache, var, DRI_INT) &&
499 !driCheckOption(&screen->optionCache, var, DRI_ENUM))
502 *val = driQueryOptioni(&screen->optionCache, var);
508 dri2ConfigQueryf(__DRIscreen *screen, const char *var, GLfloat *val)
510 if (!driCheckOption(&screen->optionCache, var, DRI_FLOAT))
513 *val = driQueryOptionf(&screen->optionCache, var);
519 static void dri_get_drawable(__DRIdrawable *pdp)
524 static void dri_put_drawable(__DRIdrawable *pdp)
533 psp = pdp->driScreenPriv;
534 (*psp->DriverAPI.DestroyBuffer)(pdp);
535 if (pdp->pClipRects && pdp->pClipRects != &pdp->dri2.clipRect) {
536 free(pdp->pClipRects);
537 pdp->pClipRects = NULL;
539 if (pdp->pBackClipRects && pdp->pClipRects != &pdp->dri2.clipRect) {
540 free(pdp->pBackClipRects);
541 pdp->pBackClipRects = NULL;
548 driDestroyDrawable(__DRIdrawable *pdp)
550 dri_put_drawable(pdp);
556 /*****************************************************************/
557 /** \name Context handling functions */
558 /*****************************************************************/
562 * Destroy the per-context private information.
565 * This function calls __DriverAPIRec::DestroyContext on \p contextPrivate, calls
566 * drmDestroyContext(), and finally frees \p contextPrivate.
569 driDestroyContext(__DRIcontext *pcp)
572 (*pcp->driScreenPriv->DriverAPI.DestroyContext)(pcp);
579 * Create the per-drawable private driver information.
581 * \param render_type Type of rendering target. \c GLX_RGBA is the only
582 * type likely to ever be supported for direct-rendering.
583 * \param shared Context with which to share textures, etc. or NULL
585 * \returns An opaque pointer to the per-context private information on
586 * success, or \c NULL on failure.
589 * This function allocates and fills a __DRIcontextRec structure. It
590 * performs some device independent initialization and passes all the
591 * relevent information to __DriverAPIRec::CreateContext to create the
595 static __DRIcontext *
596 driCreateNewContext(__DRIscreen *psp, const __DRIconfig *config,
597 int render_type, __DRIcontext *shared,
598 drm_context_t hwContext, void *data)
601 void * const shareCtx = (shared != NULL) ? shared->driverPrivate : NULL;
603 pcp = malloc(sizeof *pcp);
607 pcp->driScreenPriv = psp;
608 pcp->driDrawablePriv = NULL;
609 pcp->loaderPrivate = data;
611 pcp->dri2.draw_stamp = 0;
612 pcp->dri2.read_stamp = 0;
614 pcp->hHWContext = hwContext;
616 if ( !(*psp->DriverAPI.CreateContext)(API_OPENGL,
617 &config->modes, pcp, shareCtx) ) {
626 dri2GetAPIMask(__DRIscreen *screen)
628 return screen->api_mask;
631 static __DRIcontext *
632 dri2CreateNewContextForAPI(__DRIscreen *screen, int api,
633 const __DRIconfig *config,
634 __DRIcontext *shared, void *data)
636 __DRIcontext *context;
637 const struct gl_config *modes = (config != NULL) ? &config->modes : NULL;
638 void *shareCtx = (shared != NULL) ? shared->driverPrivate : NULL;
641 if (!(screen->api_mask & (1 << api)))
645 case __DRI_API_OPENGL:
646 mesa_api = API_OPENGL;
649 mesa_api = API_OPENGLES;
651 case __DRI_API_GLES2:
652 mesa_api = API_OPENGLES2;
658 context = malloc(sizeof *context);
662 context->driScreenPriv = screen;
663 context->driDrawablePriv = NULL;
664 context->loaderPrivate = data;
666 if (!(*screen->DriverAPI.CreateContext)(mesa_api, modes,
667 context, shareCtx) ) {
676 static __DRIcontext *
677 dri2CreateNewContext(__DRIscreen *screen, const __DRIconfig *config,
678 __DRIcontext *shared, void *data)
680 return dri2CreateNewContextForAPI(screen, __DRI_API_OPENGL,
681 config, shared, data);
685 driCopyContext(__DRIcontext *dest, __DRIcontext *src, unsigned long mask)
693 /*****************************************************************/
694 /** \name Screen handling functions */
695 /*****************************************************************/
699 * Destroy the per-screen private information.
702 * This function calls __DriverAPIRec::DestroyScreen on \p screenPrivate, calls
703 * drmClose(), and finally frees \p screenPrivate.
705 static void driDestroyScreen(__DRIscreen *psp)
708 /* No interaction with the X-server is possible at this point. This
709 * routine is called after XCloseDisplay, so there is no protocol
710 * stream open to the X-server anymore.
713 _mesa_destroy_shader_compiler();
715 if (psp->DriverAPI.DestroyScreen)
716 (*psp->DriverAPI.DestroyScreen)(psp);
718 if (!psp->dri2.enabled) {
719 (void)drmUnmap((drmAddress)psp->pSAREA, SAREA_MAX);
720 (void)drmUnmap((drmAddress)psp->pFB, psp->fbSize);
721 (void)drmCloseOnce(psp->fd);
723 driDestroyOptionCache(&psp->optionCache);
724 driDestroyOptionInfo(&psp->optionInfo);
732 setupLoaderExtensions(__DRIscreen *psp,
733 const __DRIextension **extensions)
737 for (i = 0; extensions[i]; i++) {
738 if (strcmp(extensions[i]->name, __DRI_GET_DRAWABLE_INFO) == 0)
739 psp->getDrawableInfo = (__DRIgetDrawableInfoExtension *) extensions[i];
740 if (strcmp(extensions[i]->name, __DRI_DAMAGE) == 0)
741 psp->damage = (__DRIdamageExtension *) extensions[i];
742 if (strcmp(extensions[i]->name, __DRI_SYSTEM_TIME) == 0)
743 psp->systemTime = (__DRIsystemTimeExtension *) extensions[i];
744 if (strcmp(extensions[i]->name, __DRI_DRI2_LOADER) == 0)
745 psp->dri2.loader = (__DRIdri2LoaderExtension *) extensions[i];
746 if (strcmp(extensions[i]->name, __DRI_IMAGE_LOOKUP) == 0)
747 psp->dri2.image = (__DRIimageLookupExtension *) extensions[i];
748 if (strcmp(extensions[i]->name, __DRI_USE_INVALIDATE) == 0)
749 psp->dri2.useInvalidate = (__DRIuseInvalidateExtension *) extensions[i];
754 * This is the bootstrap function for the driver. libGL supplies all of the
755 * requisite information about the system, and the driver initializes itself.
756 * This routine also fills in the linked list pointed to by \c driver_modes
757 * with the \c struct gl_config that the driver can support for windows or
762 * \param scrn Index of the screen
763 * \param ddx_version Version of the 2D DDX. This may not be meaningful for
765 * \param dri_version Version of the "server-side" DRI.
766 * \param drm_version Version of the kernel DRM.
767 * \param frame_buffer Data describing the location and layout of the
769 * \param pSAREA Pointer to the SAREA.
770 * \param fd Device handle for the DRM.
771 * \param extensions ??
772 * \param driver_modes Returns modes suppoted by the driver
773 * \param loaderPrivate ??
775 * \note There is no need to check the minimum API version in this
776 * function. Since the name of this function is versioned, it is
777 * impossible for a loader that is too old to even load this driver.
780 driCreateNewScreen(int scrn,
781 const __DRIversion *ddx_version,
782 const __DRIversion *dri_version,
783 const __DRIversion *drm_version,
784 const __DRIframebuffer *frame_buffer,
785 drmAddress pSAREA, int fd,
786 const __DRIextension **extensions,
787 const __DRIconfig ***driver_modes,
790 static const __DRIextension *emptyExtensionList[] = { NULL };
793 if (driDriverAPI.InitScreen == NULL)
796 psp = calloc(1, sizeof *psp);
800 setupLoaderExtensions(psp, extensions);
803 ** NOT_DONE: This is used by the X server to detect when the client
804 ** has died while holding the drawable lock. The client sets the
805 ** drawable lock to this value.
809 psp->drm_version = *drm_version;
810 psp->ddx_version = *ddx_version;
811 psp->dri_version = *dri_version;
813 psp->pSAREA = pSAREA;
814 psp->lock = (drmLock *) &psp->pSAREA->lock;
816 psp->pFB = frame_buffer->base;
817 psp->fbSize = frame_buffer->size;
818 psp->fbStride = frame_buffer->stride;
819 psp->fbWidth = frame_buffer->width;
820 psp->fbHeight = frame_buffer->height;
821 psp->devPrivSize = frame_buffer->dev_priv_size;
822 psp->pDevPriv = frame_buffer->dev_priv;
823 psp->fbBPP = psp->fbStride * 8 / frame_buffer->width;
825 psp->extensions = emptyExtensionList;
828 psp->dri2.enabled = GL_FALSE;
830 psp->DriverAPI = driDriverAPI;
831 psp->api_mask = (1 << __DRI_API_OPENGL);
833 *driver_modes = driDriverAPI.InitScreen(psp);
834 if (*driver_modes == NULL) {
846 dri2CreateNewScreen(int scrn, int fd,
847 const __DRIextension **extensions,
848 const __DRIconfig ***driver_configs, void *data)
850 static const __DRIextension *emptyExtensionList[] = { NULL };
852 drmVersionPtr version;
854 if (driDriverAPI.InitScreen2 == NULL)
857 psp = calloc(1, sizeof(*psp));
861 setupLoaderExtensions(psp, extensions);
863 version = drmGetVersion(fd);
865 psp->drm_version.major = version->version_major;
866 psp->drm_version.minor = version->version_minor;
867 psp->drm_version.patch = version->version_patchlevel;
868 drmFreeVersion(version);
871 psp->extensions = emptyExtensionList;
874 psp->dri2.enabled = GL_TRUE;
876 psp->DriverAPI = driDriverAPI;
877 psp->api_mask = (1 << __DRI_API_OPENGL);
878 *driver_configs = driDriverAPI.InitScreen2(psp);
879 if (*driver_configs == NULL) {
884 psp->DriverAPI = driDriverAPI;
885 psp->loaderPrivate = data;
887 driParseOptionInfo(&psp->optionInfo, __dri2ConfigOptions,
888 __dri2NConfigOptions);
889 driParseConfigFiles(&psp->optionCache, &psp->optionInfo, psp->myNum,
895 static const __DRIextension **driGetExtensions(__DRIscreen *psp)
897 return psp->extensions;
900 /** Core interface */
901 const __DRIcoreExtension driCoreExtension = {
902 { __DRI_CORE, __DRI_CORE_VERSION },
907 driIndexConfigAttrib,
918 /** Legacy DRI interface */
919 const __DRIlegacyExtension driLegacyExtension = {
920 { __DRI_LEGACY, __DRI_LEGACY_VERSION },
922 driCreateNewDrawable,
926 /** DRI2 interface */
927 const __DRIdri2Extension driDRI2Extension = {
928 { __DRI_DRI2, __DRI_DRI2_VERSION },
930 dri2CreateNewDrawable,
931 dri2CreateNewContext,
933 dri2CreateNewContextForAPI
936 const __DRI2configQueryExtension dri2ConfigQueryExtension = {
937 { __DRI2_CONFIG_QUERY, __DRI2_CONFIG_QUERY_VERSION },
944 * Calculate amount of swap interval used between GLX buffer swaps.
946 * The usage value, on the range [0,max], is the fraction of total swap
947 * interval time used between GLX buffer swaps is calculated.
949 * \f$p = t_d / (i * t_r)\f$
951 * Where \f$t_d\f$ is the time since the last GLX buffer swap, \f$i\f$ is the
952 * swap interval (as set by \c glXSwapIntervalSGI), and \f$t_r\f$ time
953 * required for a single vertical refresh period (as returned by \c
956 * See the documentation for the GLX_MESA_swap_frame_usage extension for more
959 * \param dPriv Pointer to the private drawable structure.
960 * \return If less than a single swap interval time period was required
961 * between GLX buffer swaps, a number greater than 0 and less than
962 * 1.0 is returned. If exactly one swap interval time period is
963 * required, 1.0 is returned, and if more than one is required then
964 * a number greater than 1.0 will be returned.
966 * \sa glXSwapIntervalSGI glXGetMscRateOML
968 * \todo Instead of caching the \c glXGetMscRateOML function pointer, would it
969 * be possible to cache the sync rate?
972 driCalculateSwapUsage( __DRIdrawable *dPriv, int64_t last_swap_ust,
973 int64_t current_ust )
979 __DRIscreen *psp = dPriv->driScreenPriv;
981 if ( (*psp->systemTime->getMSCRate)(dPriv, &n, &d, dPriv->loaderPrivate) ) {
982 interval = (dPriv->swap_interval != 0) ? dPriv->swap_interval : 1;
985 /* We want to calculate
986 * (current_UST - last_swap_UST) / (interval * us_per_refresh). We get
987 * current_UST by calling __glXGetUST. last_swap_UST is stored in
988 * dPriv->swap_ust. interval has already been calculated.
990 * The only tricky part is us_per_refresh. us_per_refresh is
991 * 1000000 / MSC_rate. We know the MSC_rate is n / d. We can flip it
992 * around and say us_per_refresh = 1000000 * d / n. Since this goes in
993 * the denominator of the final calculation, we calculate
994 * (interval * 1000000 * d) and move n into the numerator.
997 usage = (current_ust - last_swap_ust);
999 usage /= (interval * d);
1007 dri2InvalidateDrawable(__DRIdrawable *drawable)
1009 drawable->dri2.stamp++;