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From 93244eeb6bfa9666228c55bbebb3bd5dae42a275 Mon Sep 17 00:00:00 2001
From: Jesse Barnes <jbarnes@virtuousgeek.org>
Date: Thu, 4 Mar 2010 09:19:13 -0800
Subject: [PATCH 1/2] Merge fixes for buffer swapping from master
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commit 165a4a9c7de0fcc6ef6a6421736b412ccb35965e
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Tue Mar 23 09:47:08 2010 -0700

GLX/DRI2: expose swap control extensions if DDX support is present

Export DDX swap control status from the DRI2 module and check for it in
GLX when initializing extensions.

Reviewed-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

commit 5933b0abc6a76aaea84aa534df89900cd795c888
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Mon Mar 8 15:10:47 2010 -0800

DRI2: prevent swap wakes from waking MSC waiters

If a few swaps were queued leading to a throttle related block on the
client, and then the client submitted an MSC wait, one of the previous
swap wakeups could have caused the MSC wait to complete early.  Add a
flag for this to prevent a swap wake from prematurely waking an MSC
waiter.

Reported-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Reviewed-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

commit b00d435ddf2e9817e33bfd5f7e9b905442dc23c7
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Mon Mar 8 12:41:25 2010 -0800

DRI2: handle swapsPending better

Avoid a potential swapsPending underflow by incrementing it before
ScheduleSwap, which may complete it immediately.  And be sure to
decrement it again in case the schedule failed.

Reported-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Reviewed-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

commit 0294ff2a5cadddc8fcc77ba9a851f979f0b91fc3
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Mon Mar 8 12:39:54 2010 -0800

DRI2: throttle swaps at submission time too

We need to throttle swaps here in addition to when the context is made
current to avoid causing problems with clients that just swap.
Throttling here also ensures our swaps get ordered as long as we block
the client occasionally.

Reported-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Reviewed-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

commit db1c7cb604167baf49e61be4c09ccf7b592c4af3
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Mon Mar 8 12:38:37 2010 -0800

DRI2: advertise lowest supported DRI2 protocol version

Update our supported DRI2 protocol version as each driver does
DRI2ScreenInit, since depending on available kernel features, each DDX
may support different callbacks and therefore protocol.

Reviewed-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

commit 87ca6320f26eb3129e3c19056e1d8fa5c1784723
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Fri Mar 5 09:49:03 2010 -0800

DRI2: handle swap_interval of 0 correctly

A 0 swap interval means that swaps shouldn't be sync'd to vblank, so
just complete the swap immediately in that case.

Reviewed-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

commit 8476d99231cb725c090305d60f1c1c889d25c8dc
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Fri Mar 5 09:15:24 2010 -0800

DRI2: drawable lifetime fixes

Handle drawable destruction and lifetime correctly.

Check whether the drawable priv is valid in DRI2SwapInterval(),
DRI2WaitSBC() and DRI2WaitMSC(); it may have gone away, so be sure to
check it before using it.

If more than 1 outstanding swap is queued, we may complete several after
an app has exited.  If we free it after the first one completes and the
refcount reaches 0, we'll crash the server on subsequent completions.
So delay freeing until all swaps complete and remove the error message
as this is a normal occurence.  To do this properly, we must also avoid
destroying drawables in DRI2DestroyDrawable() if a swap or wait event is
pending.

And finally, make sure we free drawables in DRI2WaitMSCComplete() if
necessary (i.e. if the refcount has reached 0 and this MSC was the last
pending event on the object).

Reported-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Reviewed-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

commit b180e43977710b56ccfd6780f204ddcc952987a1
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Thu Mar 4 10:31:59 2010 -0800

DRI2: fix swapbuffers handling of SBC and target MSC

Returns expected SBC after completion of swap to caller, as required by
OML_sync_control spec, instead of the last_swap_target value.

Passes target_msc, divisor, remainder, correctly for
glXSwapBuffersMscOML() call, while retaining old behaviour for simple
glXSwapBuffers() call.

An OML swap can have a 0 target_msc, which just means it needs to
satisfy the divisor/remainder equation.  Pass this down to the driver as
needed so we can support it.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>

commit 751e8c09d34df4b41e8d8384a3ec1bf5cb8ca028
Author: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Date:   Sun Feb 21 05:26:00 2010 +0100

DRI2WaitSbc(): Fixes for correct semantic of glXWaitForSbcOML()

Added implementation for case target_sbc == 0. In that case, the
function shall schedule a wait until all pending swaps for the drawable
have completed.

Fix for non-blocking case. Old implementation returned random,
uninitialized values for (ust,msc,sbc) if it returned immediately
without scheduling a wait due to sbc >= target_sbc.

Now if function doesn't schedule a wait, but returns immediately,
it returns the (ust,msc,sbc) of the most recently completed swap,
i.e., the UST and MSC corresponding to the time when the returned
current SBC was reached.

Signed-off-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>

commit 0de4974b90b10fa6a447cdf980b4a114c6c9e5a8
Author: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Date:   Sun Feb 21 05:25:59 2010 +0100

DRI2: Fix glitches in DRI2SwapComplete() and DRI2WakeupClient()

DRI2SwapComplete(): Increment pPriv->swap_count++; before calling
into callback for INTEL_swap_events extension, so the swap event
contains the current SBC after swap completion instead of the
previous one.

DRI2WakeupClient: Check for pPriv->target_sbc <= pPriv->swap_count,
had wrong comparison pPriv->target_sbc >= pPriv->swap_count for
unblocking of clients of DRI2WaitSBC().

Signed-off-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>

commit 4c8ec49826a46eb3b36c69d2ad3f82320c179c38
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Thu Mar 4 09:54:15 2010 -0800

DRI2: make target_sbc signed

We need to track invalid targets as well as 0 targets, so just make it
signed so our comparisons work like they should.

Reviewed-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Reported-by: Kristian Høgsberg <krh@bitplanet.net>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

commit c4d54816f2ee4883d8f9bcf4595474fb58c95146
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Thu Mar 4 09:19:13 2010 -0800

DRI2: fixup handling of last_swap_target

We need to initialize the swap target, which is passed to the driver to
schedule events.  Rather than using -1 to indicate that the field is
uninitialized, just make sure we initialize it at drawable creation
time.

Reviewed-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
---
 glx/glxdri2.c               |   23 ++----
 hw/xfree86/dri2/dri2.c      |  174 +++++++++++++++++++++++++++++--------------
 hw/xfree86/dri2/dri2.h      |    6 ++
 hw/xfree86/dri2/dri2ext.c   |   11 ++-
 include/protocol-versions.h |    4 -
 5 files changed, 143 insertions(+), 75 deletions(-)

diff --git a/glx/glxdri2.c b/glx/glxdri2.c
index edd29b0..e791bf6 100644
--- a/glx/glxdri2.c
+++ b/glx/glxdri2.c
@@ -616,6 +616,7 @@ glxDRILeaveVT (int index, int flags)
 static void
 initializeExtensions(__GLXDRIscreen *screen)
 {
+    ScreenPtr pScreen = screen->base.pScreen;
     const __DRIextension **extensions;
     int i;
 
@@ -625,10 +626,17 @@ initializeExtensions(__GLXDRIscreen *screen)
 			 "GLX_MESA_copy_sub_buffer");
     LogMessage(X_INFO, "AIGLX: enabled GLX_MESA_copy_sub_buffer\n");
 
-    /* FIXME: only if DDX supports it */
     __glXEnableExtension(screen->glx_enable_bits, "GLX_INTEL_swap_event");
     LogMessage(X_INFO, "AIGLX: enabled GLX_INTEL_swap_event\n");
 
+    if (DRI2HasSwapControl(pScreen)) {
+	__glXEnableExtension(screen->glx_enable_bits,
+			     "GLX_SGI_swap_control");
+	__glXEnableExtension(screen->glx_enable_bits,
+			     "GLX_MESA_swap_control");
+	LogMessage(X_INFO, "AIGLX: enabled GLX_SGI_swap_control and GLX_MESA_swap_control\n");
+    }
+
     for (i = 0; extensions[i]; i++) {
 #ifdef __DRI_READ_DRAWABLE
 	if (strcmp(extensions[i]->name, __DRI_READ_DRAWABLE) == 0) {
@@ -639,19 +647,6 @@ initializeExtensions(__GLXDRIscreen *screen)
 	}
 #endif
 
-#ifdef __DRI_SWAP_CONTROL
-	if (strcmp(extensions[i]->name, __DRI_SWAP_CONTROL) == 0) {
-	    screen->swapControl =
-		(const __DRIswapControlExtension *) extensions[i];
-	    __glXEnableExtension(screen->glx_enable_bits,
-				 "GLX_SGI_swap_control");
-	    __glXEnableExtension(screen->glx_enable_bits,
-				 "GLX_MESA_swap_control");
-	    
-	    LogMessage(X_INFO, "AIGLX: enabled GLX_SGI_swap_control and GLX_MESA_swap_control\n");
-	}
-#endif
-
 #ifdef __DRI_TEX_BUFFER
 	if (strcmp(extensions[i]->name, __DRI_TEX_BUFFER) == 0) {
 	    screen->texBuffer =
diff --git a/hw/xfree86/dri2/dri2.c b/hw/xfree86/dri2/dri2.c
index 48618e1..2bdb733 100644
--- a/hw/xfree86/dri2/dri2.c
+++ b/hw/xfree86/dri2/dri2.c
@@ -45,6 +45,9 @@
 
 #include "xf86.h"
 
+CARD8 dri2_major; /* version of DRI2 supported by DDX */
+CARD8 dri2_minor;
+
 static int dri2ScreenPrivateKeyIndex;
 static DevPrivateKey dri2ScreenPrivateKey = &dri2ScreenPrivateKeyIndex;
 static int dri2WindowPrivateKeyIndex;
@@ -60,10 +63,13 @@ typedef struct _DRI2Drawable {
     int			 bufferCount;
     unsigned int	 swapsPending;
     ClientPtr		 blockedClient;
+    Bool		 blockedOnMsc;
     int			 swap_interval;
     CARD64		 swap_count;
-    CARD64		 target_sbc; /* -1 means no SBC wait outstanding */
+    int64_t		 target_sbc; /* -1 means no SBC wait outstanding */
     CARD64		 last_swap_target; /* most recently queued swap target */
+    CARD64		 last_swap_msc; /* msc at completion of most recent swap */
+    CARD64		 last_swap_ust; /* ust at completion of most recent swap */
     int			 swap_limit; /* for N-buffering */
 } DRI2DrawableRec, *DRI2DrawablePtr;
 
@@ -116,9 +122,11 @@ DRI2GetDrawable(DrawablePtr pDraw)
 int
 DRI2CreateDrawable(DrawablePtr pDraw)
 {
+    DRI2ScreenPtr   ds = DRI2GetScreen(pDraw->pScreen);
     WindowPtr	    pWin;
     PixmapPtr	    pPixmap;
     DRI2DrawablePtr pPriv;
+    CARD64          ust;
 
     pPriv = DRI2GetDrawable(pDraw);
     if (pPriv != NULL)
@@ -138,11 +146,17 @@ DRI2CreateDrawable(DrawablePtr pDraw)
     pPriv->bufferCount = 0;
     pPriv->swapsPending = 0;
     pPriv->blockedClient = NULL;
+    pPriv->blockedOnMsc = FALSE;
     pPriv->swap_count = 0;
     pPriv->target_sbc = -1;
     pPriv->swap_interval = 1;
-    pPriv->last_swap_target = -1;
+    /* Initialize last swap target from DDX if possible */
+    if (!ds->GetMSC || !(*ds->GetMSC)(pDraw, &ust, &pPriv->last_swap_target))
+	pPriv->last_swap_target = 0;
+
     pPriv->swap_limit = 1; /* default to double buffering */
+    pPriv->last_swap_msc = 0;
+    pPriv->last_swap_ust = 0;
 
     if (pDraw->type == DRAWABLE_WINDOW)
     {
@@ -390,6 +404,15 @@ DRI2ThrottleClient(ClientPtr client, DrawablePtr pDraw)
     return FALSE;
 }
 
+static void
+__DRI2BlockClient(ClientPtr client, DRI2DrawablePtr pPriv)
+{
+    if (pPriv->blockedClient == NULL) {
+	IgnoreClient(client);
+	pPriv->blockedClient = client;
+    }
+}
+
 void
 DRI2BlockClient(ClientPtr client, DrawablePtr pDraw)
 {
@@ -399,10 +422,8 @@ DRI2BlockClient(ClientPtr client, DrawablePtr pDraw)
     if (pPriv == NULL)
 	return;
 
-    if (pPriv->blockedClient == NULL) {
-	IgnoreClient(client);
-	pPriv->blockedClient = client;
-    }
+    __DRI2BlockClient(client, pPriv);
+    pPriv->blockedOnMsc = TRUE;
 }
 
 int
@@ -483,6 +504,11 @@ DRI2WaitMSCComplete(ClientPtr client, DrawablePtr pDraw, int frame,
 	AttendClient(pPriv->blockedClient);
 
     pPriv->blockedClient = NULL;
+    pPriv->blockedOnMsc = FALSE;
+
+    /* If there's still a swap pending, let DRI2SwapComplete free it */
+    if (pPriv->refCount == 0 && pPriv->swapsPending == 0)
+	DRI2FreeDrawable(pDraw);
 }
 
 static void
@@ -500,21 +526,26 @@ DRI2WakeClient(ClientPtr client, DrawablePtr pDraw, int frame,
     }
 
     /*
-     * Swap completed.  Either wake up an SBC waiter or a client that was
-     * blocked due to GLX activity during a swap.
+     * Swap completed.
+     * Wake the client iff:
+     *   - it was waiting on SBC
+     *   - was blocked due to GLX make current
+     *   - was blocked due to swap throttling
+     *   - is not blocked due to an MSC wait
      */
     if (pPriv->target_sbc != -1 &&
-	pPriv->target_sbc >= pPriv->swap_count) {
+	pPriv->target_sbc <= pPriv->swap_count) {
 	ProcDRI2WaitMSCReply(client, ((CARD64)tv_sec * 1000000) + tv_usec,
 			     frame, pPriv->swap_count);
 	pPriv->target_sbc = -1;
 
 	AttendClient(pPriv->blockedClient);
 	pPriv->blockedClient = NULL;
-    } else if (pPriv->target_sbc == -1) {
-	if (pPriv->blockedClient)
+    } else if (pPriv->target_sbc == -1 && !pPriv->blockedOnMsc) {
+	if (pPriv->blockedClient) {
 	    AttendClient(pPriv->blockedClient);
-	pPriv->blockedClient = NULL;
+	    pPriv->blockedClient = NULL;
+	}
     }
 }
 
@@ -534,21 +565,24 @@ DRI2SwapComplete(ClientPtr client, DrawablePtr pDraw, int frame,
 	return;
     }
 
-    if (pPriv->refCount == 0) {
-        xf86DrvMsg(pScreen->myNum, X_ERROR,
-		   "[DRI2] %s: bad drawable refcount\n", __func__);
-	DRI2FreeDrawable(pDraw);
-	return;
-    }
+    pPriv->swapsPending--;
+    pPriv->swap_count++;
 
     ust = ((CARD64)tv_sec * 1000000) + tv_usec;
     if (swap_complete)
 	swap_complete(client, swap_data, type, ust, frame, pPriv->swap_count);
 
-    pPriv->swapsPending--;
-    pPriv->swap_count++;
+    pPriv->last_swap_msc = frame;
+    pPriv->last_swap_ust = ust;
 
     DRI2WakeClient(client, pDraw, frame, tv_sec, tv_usec);
+
+    /*
+     * It's normal for the app to have exited with a swap outstanding, but
+     * don't free the drawable until they're all complete.
+     */
+    if (pPriv->swapsPending == 0 && pPriv->refCount == 0)
+	DRI2FreeDrawable(pDraw);
 }
 
 Bool
@@ -563,7 +597,7 @@ DRI2WaitSwap(ClientPtr client, DrawablePtr pDrawable)
 	pPriv->blockedClient == NULL) {
 	ResetCurrentRequest(client);
 	client->sequence--;
-	DRI2BlockClient(client, pDrawable);
+	__DRI2BlockClient(client, pPriv);
 	return TRUE;
     }
 
@@ -579,7 +613,6 @@ DRI2SwapBuffers(ClientPtr client, DrawablePtr pDraw, CARD64 target_msc,
     DRI2ScreenPtr   ds = DRI2GetScreen(pDraw->pScreen);
     DRI2DrawablePtr pPriv;
     DRI2BufferPtr   pDestBuffer = NULL, pSrcBuffer = NULL;
-    CARD64          ust;
     int             ret, i;
 
     pPriv = DRI2GetDrawable(pDraw);
@@ -601,8 +634,8 @@ DRI2SwapBuffers(ClientPtr client, DrawablePtr pDraw, CARD64 target_msc,
 	return BadDrawable;
     }
 
-    /* Old DDX, just blit */
-    if (!ds->ScheduleSwap) {
+    /* Old DDX or no swap interval, just blit */
+    if (!ds->ScheduleSwap || !pPriv->swap_interval) {
 	BoxRec box;
 	RegionRec region;
 
@@ -623,52 +656,52 @@ DRI2SwapBuffers(ClientPtr client, DrawablePtr pDraw, CARD64 target_msc,
     /*
      * In the simple glXSwapBuffers case, all params will be 0, and we just
      * need to schedule a swap for the last swap target + the swap interval.
-     * If the last swap target hasn't been set yet, call into the driver
-     * to get the current count.
      */
-    if (target_msc == 0 && divisor == 0 && remainder == 0 &&
-	pPriv->last_swap_target < 0) {
-	ret = (*ds->GetMSC)(pDraw, &ust, &target_msc);
-	if (!ret) {
-	    xf86DrvMsg(pScreen->myNum, X_ERROR,
-		       "[DRI2] %s: driver failed to return current MSC\n",
-		       __func__);
-	    return BadDrawable;
-	}
+    if (target_msc == 0 && divisor == 0 && remainder == 0) {
+	/*
+	 * Swap target for this swap is last swap target + swap interval since
+	 * we have to account for the current swap count, interval, and the
+	 * number of pending swaps.
+	 */
+	*swap_target = pPriv->last_swap_target + pPriv->swap_interval;
+    } else {
+	/* glXSwapBuffersMscOML could have a 0 target_msc, honor it */
+	*swap_target = target_msc;
     }
 
-    /* First swap needs to initialize last_swap_target */
-    if (pPriv->last_swap_target < 0)
-	pPriv->last_swap_target = target_msc;
-
-    /*
-     * Swap target for this swap is last swap target + swap interval since
-     * we have to account for the current swap count, interval, and the
-     * number of pending swaps.
-     */
-    *swap_target = pPriv->last_swap_target + pPriv->swap_interval;
-
+    pPriv->swapsPending++;
     ret = (*ds->ScheduleSwap)(client, pDraw, pDestBuffer, pSrcBuffer,
 			      swap_target, divisor, remainder, func, data);
     if (!ret) {
+	pPriv->swapsPending--; /* didn't schedule */
         xf86DrvMsg(pScreen->myNum, X_ERROR,
 		   "[DRI2] %s: driver failed to schedule swap\n", __func__);
 	return BadDrawable;
     }
 
-    pPriv->swapsPending++;
     pPriv->last_swap_target = *swap_target;
 
+    /* According to spec, return expected swapbuffers count SBC after this swap
+     * will complete.
+     */
+    *swap_target = pPriv->swap_count + pPriv->swapsPending;
+
     return Success;
 }
 
 void
 DRI2SwapInterval(DrawablePtr pDrawable, int interval)
 {
+    ScreenPtr       pScreen = pDrawable->pScreen;
     DRI2DrawablePtr pPriv = DRI2GetDrawable(pDrawable);
 
-    /* fixme: check against arbitrary max? */
+    if (pPriv == NULL) {
+        xf86DrvMsg(pScreen->myNum, X_ERROR,
+		   "[DRI2] %s: bad drawable\n", __func__);
+	return;
+    }
 
+    /* fixme: check against arbitrary max? */
     pPriv->swap_interval = interval;
 }
 
@@ -717,7 +750,7 @@ DRI2WaitMSC(ClientPtr client, DrawablePtr pDraw, CARD64 target_msc,
     Bool ret;
 
     pPriv = DRI2GetDrawable(pDraw);
-    if (pPriv == NULL)
+    if (pPriv == NULL || pPriv->refCount == 0)
 	return BadDrawable;
 
     /* Old DDX just completes immediately */
@@ -741,14 +774,28 @@ DRI2WaitSBC(ClientPtr client, DrawablePtr pDraw, CARD64 target_sbc,
     DRI2DrawablePtr pPriv;
 
     pPriv = DRI2GetDrawable(pDraw);
-    if (pPriv == NULL)
+    if (pPriv == NULL || pPriv->refCount == 0)
 	return BadDrawable;
 
-    if (pPriv->swap_count >= target_sbc)
-	return Success;
+    /* target_sbc == 0 means to block until all pending swaps are
+     * finished. Recalculate target_sbc to get that behaviour.
+     */
+    if (target_sbc == 0)
+        target_sbc = pPriv->swap_count + pPriv->swapsPending;
+
+    /* If current swap count already >= target_sbc,
+     * return immediately with (ust, msc, sbc) triplet of
+     * most recent completed swap.
+     */
+    if (pPriv->swap_count >= target_sbc) {
+        *sbc = pPriv->swap_count;
+        *msc = pPriv->last_swap_msc;
+        *ust = pPriv->last_swap_ust;
+        return Success;
+    }
 
     pPriv->target_sbc = target_sbc;
-    DRI2BlockClient(client, pDraw);
+    __DRI2BlockClient(client, pPriv);
 
     return Success;
 }
@@ -776,14 +823,22 @@ DRI2DestroyDrawable(DrawablePtr pDraw)
 	xfree(pPriv->buffers);
     }
 
-    /* If the window is destroyed while we have a swap pending, don't
+    /* If the window is destroyed while we have a swap or wait pending, don't
      * actually free the priv yet.  We'll need it in the DRI2SwapComplete()
      * callback and we'll free it there once we're done. */
-    if (!pPriv->swapsPending)
+    if (!pPriv->swapsPending && !pPriv->blockedClient)
 	DRI2FreeDrawable(pDraw);
 }
 
 Bool
+DRI2HasSwapControl(ScreenPtr pScreen)
+{
+    DRI2ScreenPtr ds = DRI2GetScreen(pScreen);
+
+    return (ds->ScheduleSwap && ds->GetMSC);
+}
+
+Bool
 DRI2Connect(ScreenPtr pScreen, unsigned int driverType, int *fd,
 	    const char **driverName, const char **deviceName)
 {
@@ -820,6 +875,7 @@ DRI2ScreenInit(ScreenPtr pScreen, DRI2InfoPtr info)
 	"VDPAU", /* DRI2DriverVDPAU */
     };
     unsigned int i;
+    CARD8 cur_minor;
 
     if (info->version < 3)
 	return FALSE;
@@ -836,6 +892,7 @@ DRI2ScreenInit(ScreenPtr pScreen, DRI2InfoPtr info)
 
     ds->fd	       = info->fd;
     ds->deviceName     = info->deviceName;
+    dri2_major         = 1;
 
     ds->CreateBuffer   = info->CreateBuffer;
     ds->DestroyBuffer  = info->DestroyBuffer;
@@ -845,8 +902,15 @@ DRI2ScreenInit(ScreenPtr pScreen, DRI2InfoPtr info)
 	ds->ScheduleSwap = info->ScheduleSwap;
 	ds->ScheduleWaitMSC = info->ScheduleWaitMSC;
 	ds->GetMSC = info->GetMSC;
+	cur_minor = 2;
+    } else {
+	cur_minor = 1;
     }
 
+    /* Initialize minor if needed and set to minimum provied by DDX */
+    if (!dri2_minor || dri2_minor > cur_minor)
+	dri2_minor = cur_minor;
+
     if (info->version == 3 || info->numDrivers == 0) {
 	/* Driver too old: use the old-style driverName field */
 	ds->numDrivers = 1;
diff --git a/hw/xfree86/dri2/dri2.h b/hw/xfree86/dri2/dri2.h
index 1c8626b..ce8a5df 100644
--- a/hw/xfree86/dri2/dri2.h
+++ b/hw/xfree86/dri2/dri2.h
@@ -46,6 +46,9 @@ typedef struct {
     void *driverPrivate;
 } DRI2BufferRec, *DRI2BufferPtr;
 
+extern CARD8 dri2_major; /* version of DRI2 supported by DDX */
+extern CARD8 dri2_minor;
+
 typedef DRI2BufferRec DRI2Buffer2Rec, *DRI2Buffer2Ptr;
 typedef void (*DRI2SwapEventPtr)(ClientPtr client, void *data, int type,
 				 CARD64 ust, CARD64 msc, CARD64 sbc);
@@ -185,6 +188,8 @@ extern _X_EXPORT Bool DRI2ScreenInit(ScreenPtr	pScreen,
 
 extern _X_EXPORT void DRI2CloseScreen(ScreenPtr pScreen);
 
+extern _X_EXPORT Bool DRI2HasSwapControl(ScreenPtr pScreen);
+
 extern _X_EXPORT Bool DRI2Connect(ScreenPtr pScreen,
 		 unsigned int driverType,
 		 int *fd,
@@ -254,6 +259,7 @@ extern _X_EXPORT Bool DRI2CanFlip(DrawablePtr pDraw);
 
 extern _X_EXPORT Bool DRI2CanExchange(DrawablePtr pDraw);
 
+/* Note: use *only* for MSC related waits */
 extern _X_EXPORT void DRI2BlockClient(ClientPtr client, DrawablePtr pDraw);
 
 extern _X_EXPORT void DRI2SwapComplete(ClientPtr client, DrawablePtr pDraw,
diff --git a/hw/xfree86/dri2/dri2ext.c b/hw/xfree86/dri2/dri2ext.c
index bd92fd3..094d54d 100644
--- a/hw/xfree86/dri2/dri2ext.c
+++ b/hw/xfree86/dri2/dri2ext.c
@@ -80,8 +80,8 @@ ProcDRI2QueryVersion(ClientPtr client)
     rep.type = X_Reply;
     rep.length = 0;
     rep.sequenceNumber = client->sequence;
-    rep.majorVersion = SERVER_DRI2_MAJOR_VERSION;
-    rep.minorVersion = SERVER_DRI2_MINOR_VERSION;
+    rep.majorVersion = dri2_major;
+    rep.minorVersion = dri2_minor;
 
     if (client->swapped) {
     	swaps(&rep.sequenceNumber, n);
@@ -384,6 +384,13 @@ ProcDRI2SwapBuffers(ClientPtr client)
 		       DixReadAccess | DixWriteAccess, &pDrawable, &status))
 	return status;
 
+    /*
+     * Ensures an out of control client can't exhaust our swap queue, and
+     * also orders swaps.
+     */
+    if (DRI2ThrottleClient(client, pDrawable))
+	return client->noClientException;
+
     target_msc = vals_to_card64(stuff->target_msc_lo, stuff->target_msc_hi);
     divisor = vals_to_card64(stuff->divisor_lo, stuff->divisor_hi);
     remainder = vals_to_card64(stuff->remainder_lo, stuff->remainder_hi);
diff --git a/include/protocol-versions.h b/include/protocol-versions.h
index c74b7fa..97ef5da 100644
--- a/include/protocol-versions.h
+++ b/include/protocol-versions.h
@@ -51,10 +51,6 @@
 #define SERVER_DMX_MINOR_VERSION		2
 #define SERVER_DMX_PATCH_VERSION		20040604
 
-/* DRI2 */
-#define SERVER_DRI2_MAJOR_VERSION		1
-#define SERVER_DRI2_MINOR_VERSION		2
-
 /* Generic event extension */
 #define SERVER_GE_MAJOR_VERSION                 1
 #define SERVER_GE_MINOR_VERSION                 0
-- 
1.7.0.1