Refactor and fix core vblank support

Consolidate support for synchronizing to and retrieving vblank counters.  Also
fix the core vblank code to return monotonic MSC counters, which are required
by some GLX extensions.  Adding support for multiple pipes to a low level
driver is fairly easy, the Intel 965 driver provides simple example code (see
intel_buffers.c:intelWindowMoved()).

The new code bumps the media stream counter extension version to 2 and adds a
new getDrawableMSC callback.  This callback takes a drawablePrivate pointer,
which is used to calculate the MSC value seen by clients based on the actual
vblank counter(s) returned from the kernel.  The new drawable private fields
are as follows:
  - vblSeq - used for tracking vblank counts for buffer swapping
  - vblFlags - flags (e.g. current pipe), updated by low level driver
  - msc_base - MSC counter from the last time the current pipe changed
  - vblank_base - kernel DRM vblank counter from the last time the pipe changed

Using the above variables, the core vblank code (in vblank.c) can calculate a
monotonic MSC value.  The low level DRI drivers are responsible for updating
the current pipe (by setting VBLANK_FLAG_SECONDARY for example in vblFlags)
along with msc_base and vblank_base whenever the pipe associated with a given
drawable changes (again, see intelWindowMoved for an example of this).

Drivers should fill in the GetDrawableMSC DriverAPIRec field to point to
driDrawableGetMSC32 and add code for pipe switching as outlined above to fully
support the new scheme.

3 files changed, 6 insertions, 10 deletions

diff --git a/src/mesa/drivers/dri/mga/mga_xmesa.c b/src/mesa/drivers/dri/mga/mga_xmesa.c
index 2f3516fd38..31042f9739 100644
--- a/src/mesa/drivers/dri/mga/mga_xmesa.c
+++ b/src/mesa/drivers/dri/mga/mga_xmesa.c
@@ -452,6 +452,7 @@ mgaCreateContext( const __GLcontextModes *mesaVis,
    GLcontext *ctx, *shareCtx;
    mgaContextPtr mmesa;
    __DRIscreenPrivate *sPriv = driContextPriv->driScreenPriv;
+   __DRIdrawablePrivate *dPriv = driContextPriv->driDrawablePriv;
    mgaScreenPrivate *mgaScreen = (mgaScreenPrivate *)sPriv->private;
    drm_mga_sarea_t *saPriv = (drm_mga_sarea_t *)(((char*)sPriv->pSAREA)+
 					      mgaScreen->sarea_priv_offset);
@@ -650,7 +651,7 @@ mgaCreateContext( const __GLcontextModes *mesaVis,
 				    debug_control );
 #endif
 
-   mmesa->vblank_flags = (mmesa->mgaScreen->irq == 0)
+   dPriv->vblFlags = (mmesa->mgaScreen->irq == 0)
        ? VBLANK_FLAG_NO_IRQ : driGetDefaultVBlankFlags(&mmesa->optionCache);
 
    (*dri_interface->getUST)( & mmesa->swap_ust );
@@ -882,8 +883,8 @@ mgaMakeCurrent(__DRIcontextPrivate *driContextPriv,
       mgaContextPtr mmesa = (mgaContextPtr) driContextPriv->driverPrivate;
 
       if (mmesa->driDrawable != driDrawPriv) {
-	 driDrawableInitVBlank( driDrawPriv, mmesa->vblank_flags,
-				&mmesa->vbl_seq );
+	 driDrawableInitVBlank( driDrawPriv );
+
 	 mmesa->driDrawable = driDrawPriv;
 	 mmesa->dirty = ~0; 
 	 mmesa->dirty_cliprects = (MGA_FRONT|MGA_BACK); 
@@ -948,6 +949,7 @@ static const struct __DriverAPIRec mgaAPI = {
    .UnbindContext   = mgaUnbindContext,
    .GetSwapInfo     = getSwapInfo,
    .GetMSC          = driGetMSC32,
+   .GetDrawableMSC  = driDrawableGetMSC32,
    .WaitForMSC      = driWaitForMSC32,
    .WaitForSBC      = NULL,
    .SwapBuffersMSC  = NULL
diff --git a/src/mesa/drivers/dri/mga/mgacontext.h b/src/mesa/drivers/dri/mga/mgacontext.h
index 2124006ade..2681976fc2 100644
--- a/src/mesa/drivers/dri/mga/mgacontext.h
+++ b/src/mesa/drivers/dri/mga/mgacontext.h
@@ -258,11 +258,6 @@ struct mga_context_t {
    drmBufPtr  vertex_dma_buffer;
    drmBufPtr  iload_buffer;
 
-   /* VBI
-    */
-   GLuint vbl_seq;
-   GLuint vblank_flags;
-
    int64_t swap_ust;
    int64_t swap_missed_ust;
 
diff --git a/src/mesa/drivers/dri/mga/mgaioctl.c b/src/mesa/drivers/dri/mga/mgaioctl.c
index 679d688925..94126a31f9 100644
--- a/src/mesa/drivers/dri/mga/mgaioctl.c
+++ b/src/mesa/drivers/dri/mga/mgaioctl.c
@@ -428,8 +428,7 @@ void mgaCopyBuffer( const __DRIdrawablePrivate *dPriv )
    FLUSH_BATCH( mmesa );
 
    mgaWaitForFrameCompletion( mmesa );
-   driWaitForVBlank( dPriv, & mmesa->vbl_seq, mmesa->vblank_flags,
-		     & missed_target );
+   driWaitForVBlank( dPriv, & dPriv->vblSeq, dPriv->vblFlags, & missed_target );
    if ( missed_target ) {
       mmesa->swap_missed_count++;
       (void) (*dri_interface->getUST)( & mmesa->swap_missed_ust );