sna/present: Compensate for time elapsed since last swap

When computing the delay for the fake flip, compensate for any time
elapsed since the last frame in order to hit the desired vblank more
accurately. A side-effect of this is that we may now compute 0 delay
timers which require special handling.

Testcase: present-test/accuracy
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 201 insertions, 25 deletions

diff --git a/test/present-test.c b/test/present-test.c
index 6f6d6a88..9e5e96b0 100644
--- a/test/present-test.c
+++ b/test/present-test.c
@@ -45,6 +45,7 @@
 #include <xcb/xcb.h>
 #include <xcb/present.h>
 #include <xcb/xfixes.h>
+#include <xcb/dri3.h>
 #include <xf86drm.h>
 #include <i915_drm.h>
 
@@ -138,9 +139,11 @@ static void *setup_msc(Display *dpy,  Window win)
 static uint64_t check_msc(Display *dpy, Window win, void *q, uint64_t last_msc)
 {
 	xcb_connection_t *c = XGetXCBConnection(dpy);
+	static uint32_t serial = 1;
 	uint64_t msc = 0;
+	int complete = 0;
 
-	xcb_present_notify_msc(c, win, 0, 0, 0, 0);
+	xcb_present_notify_msc(c, win, serial, 0, 0, 0);
 	xcb_flush(c);
 
 	do {
@@ -152,16 +155,22 @@ static uint64_t check_msc(Display *dpy, Window win, void *q, uint64_t last_msc)
 			break;
 
 		ce = (xcb_present_complete_notify_event_t *)ev;
-		if (ce->kind != XCB_PRESENT_COMPLETE_KIND_PIXMAP)
+		if (ce->kind == XCB_PRESENT_COMPLETE_KIND_NOTIFY_MSC &&
+		    ce->serial == serial) {
 			msc = ce->msc;
+			complete = 1;
+		}
 		free(ev);
-	} while (msc == 0);
+	} while (!complete);
 
 	if (msc < last_msc) {
 		printf("Invalid MSC: was %llu, now %llu\n",
 		       (long long)last_msc, (long long)msc);
 	}
 
+	if (++serial == 0)
+		serial = 1;
+
 	return msc;
 }
 
@@ -191,8 +200,7 @@ static int test_whole(Display *dpy)
 	xshmfence_reset(fence.addr);
 
 	pixmap = XCreatePixmap(dpy, root, width, height, depth);
-	xcb_present_pixmap(c, root, pixmap,
-			   0, /* sbc */
+	xcb_present_pixmap(c, root, pixmap, 0,
 			   0, /* valid */
 			   0, /* update */
 			   0, /* x_off */
@@ -208,8 +216,7 @@ static int test_whole(Display *dpy)
 	XFreePixmap(dpy, pixmap);
 
 	pixmap = XCreatePixmap(dpy, root, width, height, depth);
-	xcb_present_pixmap(c, root, pixmap,
-			   0, /* sbc */
+	xcb_present_pixmap(c, root, pixmap, 0,
 			   0, /* valid */
 			   0, /* update */
 			   0, /* x_off */
@@ -244,8 +251,9 @@ static int test_future(Display *dpy, void *Q)
 	xcb_xfixes_region_t region;
 	unsigned int width, height;
 	unsigned border, depth;
-	int x, y, ret = 1, n;
+	int x, y, ret = 0, n;
 	uint64_t target, final;
+	int complete;
 
 	XGetGeometry(dpy, DefaultRootWindow(dpy),
 		     &root, &x, &y, &width, &height, &border, &depth);
@@ -263,8 +271,7 @@ static int test_future(Display *dpy, void *Q)
 	pixmap = XCreatePixmap(dpy, root, width, height, depth);
 	xshmfence_reset(fence.addr);
 	for (n = N_VBLANKS; n--; )
-		xcb_present_pixmap(c, root, pixmap,
-				   n, /* sbc */
+		xcb_present_pixmap(c, root, pixmap, 0,
 				   0, /* valid */
 				   region, /* update */
 				   0, /* x_off */
@@ -277,8 +284,7 @@ static int test_future(Display *dpy, void *Q)
 				   1, /* divisor */
 				   0, /* remainder */
 				   0, NULL);
-	xcb_present_pixmap(c, root, pixmap,
-			   N_VBLANKS, /* sbc */
+	xcb_present_pixmap(c, root, pixmap, 0,
 			   region, /* valid */
 			   region, /* update */
 			   0, /* x_off */
@@ -294,7 +300,7 @@ static int test_future(Display *dpy, void *Q)
 	xcb_flush(c);
 
 	XSync(dpy, True);
-	ret = !!xshmfence_await(fence.addr);
+	ret += !!xshmfence_await(fence.addr);
 
 	final = check_msc(dpy, root, Q, 0);
 	if (final < target) {
@@ -308,8 +314,7 @@ static int test_future(Display *dpy, void *Q)
 	}
 
 	xshmfence_reset(fence.addr);
-	xcb_present_pixmap(c, root, pixmap,
-			   N_VBLANKS, /* sbc */
+	xcb_present_pixmap(c, root, pixmap, 0,
 			   region, /* valid */
 			   region, /* update */
 			   0, /* x_off */
@@ -323,7 +328,7 @@ static int test_future(Display *dpy, void *Q)
 			   0, /* remainder */
 			   0, NULL);
 	xcb_flush(c);
-	ret = !!xshmfence_await(fence.addr);
+	ret += !!xshmfence_await(fence.addr);
 
 	final = check_msc(dpy, root, Q, 0);
 	if (final < target + N_VBLANKS) {
@@ -336,6 +341,37 @@ static int test_future(Display *dpy, void *Q)
 		ret++;
 	}
 
+	xcb_present_pixmap(c, root, pixmap, 0xdeadbeef,
+			   0, /* valid */
+			   0, /* update */
+			   0, /* x_off */
+			   0, /* y_off */
+			   None,
+			   None, /* wait fence */
+			   0,
+			   XCB_PRESENT_OPTION_NONE,
+			   final + N_VBLANKS + 1, /* target msc */
+			   0, /* divisor */
+			   0, /* remainder */
+			   0, NULL);
+	xcb_flush(c);
+	complete = 0;
+	do {
+		xcb_present_complete_notify_event_t *ce;
+		xcb_generic_event_t *ev;
+
+		ev = xcb_wait_for_special_event(c, Q);
+		if (ev == NULL)
+			break;
+
+		ce = (xcb_present_complete_notify_event_t *)ev;
+		if (ce->kind != XCB_PRESENT_COMPLETE_KIND_PIXMAP)
+			break;
+
+		complete = ce->serial == 0xdeadbeef;
+		free(ev);
+	} while (!complete);
+
 	XFreePixmap(dpy, pixmap);
 	xcb_xfixes_destroy_region(c, region);
 	dri3_fence_free(dpy, &fence);
@@ -344,6 +380,121 @@ static int test_future(Display *dpy, void *Q)
 	ret += !!_x_error_occurred;
 
 	return ret;
+#undef N_VBLANKS
+}
+
+static int test_accuracy(Display *dpy, void *Q)
+{
+#define N_VBLANKS (60 * 120) /* ~2 minutes */
+	xcb_connection_t *c = XGetXCBConnection(dpy);
+	Pixmap pixmap;
+	Window root;
+	unsigned int width, height;
+	unsigned border, depth;
+	int x, y, ret = 0, n;
+	uint64_t target;
+	int early = 0, late = 0;
+	int complete;
+
+	XGetGeometry(dpy, DefaultRootWindow(dpy),
+		     &root, &x, &y, &width, &height, &border, &depth);
+
+	printf("Testing whole screen flip acccuracy: %dx%d\n", width, height);
+	_x_error_occurred = 0;
+
+	target = check_msc(dpy, root, Q, 0);
+	pixmap = XCreatePixmap(dpy, root, width, height, depth);
+	xcb_present_pixmap(c, root, pixmap,
+			   0xdeadbeef, /* serial */
+			   0, /* valid */
+			   0, /* update */
+			   0, /* x_off */
+			   0, /* y_off */
+			   None,
+			   None, /* wait fence */
+			   None,
+			   XCB_PRESENT_OPTION_NONE,
+			   target + 60, /* target msc */
+			   0, /* divisor */
+			   0, /* remainder */
+			   0, NULL);
+	xcb_flush(c);
+	complete = 0;
+	do {
+		xcb_present_complete_notify_event_t *ce;
+		xcb_generic_event_t *ev;
+
+		ev = xcb_wait_for_special_event(c, Q);
+		if (ev == NULL)
+			break;
+
+		ce = (xcb_present_complete_notify_event_t *)ev;
+		if (ce->kind != XCB_PRESENT_COMPLETE_KIND_PIXMAP)
+			break;
+
+		complete = ce->serial == 0xdeadbeef;
+		free(ev);
+	} while (!complete);
+	XSync(dpy, True);
+
+	target = check_msc(dpy, root, Q, 0);
+	for (n = 0; n <= N_VBLANKS; n++)
+		xcb_present_pixmap(c, root, pixmap,
+				   target + 60 + n, /* serial */
+				   0, /* valid */
+				   0, /* update */
+				   0, /* x_off */
+				   0, /* y_off */
+				   None,
+				   None, /* wait fence */
+				   None,
+				   XCB_PRESENT_OPTION_NONE,
+				   target + 60 + n, /* target msc */
+				   0, /* divisor */
+				   0, /* remainder */
+				   0, NULL);
+	xcb_flush(c);
+
+	complete = 0;
+	do {
+		xcb_present_complete_notify_event_t *ce;
+		xcb_generic_event_t *ev;
+		int64_t msc;
+
+		ev = xcb_wait_for_special_event(c, Q);
+		if (ev == NULL)
+			break;
+
+		ce = (xcb_present_complete_notify_event_t *)ev;
+		if (ce->kind != XCB_PRESENT_COMPLETE_KIND_PIXMAP)
+			break;
+
+		assert(ce->serial);
+
+		msc = ce->msc - ce->serial;
+		if (msc < 0) {
+			fprintf(stderr, "frame %d displayed early by %lld frames\n", (int)(ce->serial - target - 60), (long long)msc);
+			ret += -msc;
+			early++;
+		} else if (msc > 1) { /* allow the frame to slip by a vblank */
+			ret += msc;
+			late++;
+		}
+		complete = ce->serial == target + 60 + N_VBLANKS;
+		free(ev);
+	} while (!complete);
+
+	if (early)
+		printf("%d frames shown too early! ", early);
+	if (late)
+		printf("%d fames shown too late!", late);
+	if (early|late)
+		printf("\n");
+
+	ret += !!_x_error_occurred;
+
+	return ret;
+#undef N_VBLANKS
 }
 
 static inline XRRScreenResources *_XRRGetScreenResourcesCurrent(Display *dpy, Window window)
@@ -447,6 +598,7 @@ struct test_crtc {
 	uint64_t msc;
 };
 #define SYNC 0x1
+#define FUTURE 0x2
 
 static int __test_crtc(Display *dpy, RRCrtc crtc,
 		       int width, int height,
@@ -473,16 +625,14 @@ static int __test_crtc(Display *dpy, RRCrtc crtc,
 			   None, /* wait fence */
 			   test->flags & SYNC ? test->fence.xid : None,
 			   XCB_PRESENT_OPTION_NONE,
-			   0, /* target msc */
+			   test->msc, /* target msc */
 			   1, /* divisor */
 			   0, /* remainder */
 			   0, NULL);
-	XFreePixmap(dpy, pixmap);
-
 	if (test->flags & SYNC) {
-		pixmap = XCreatePixmap(dpy, test->win, width, height, test->depth);
+		Pixmap tmp = XCreatePixmap(dpy, test->win, width, height, test->depth);
 		xcb_present_pixmap(XGetXCBConnection(dpy),
-				   test->win, pixmap,
+				   test->win, tmp,
 				   1, /* sbc */
 				   0, /* valid */
 				   0, /* update */
@@ -492,14 +642,15 @@ static int __test_crtc(Display *dpy, RRCrtc crtc,
 				   None, /* wait fence */
 				   None, /* sync fence */
 				   XCB_PRESENT_OPTION_NONE,
-				   1, /* target msc */
+				   test->msc + (test->flags & FUTURE ? 5 * 16 : 1), /* target msc */
 				   1, /* divisor */
 				   0, /* remainder */
 				   0, NULL);
-		XFreePixmap(dpy, pixmap);
+		XFreePixmap(dpy, tmp);
 		XFlush(dpy);
 		err += !!xshmfence_await(test->fence.addr);
 	}
+	XFreePixmap(dpy, pixmap);
 
 	test->msc = check_msc(dpy, test->win, test->queue, test->msc);
 	return err;
@@ -532,6 +683,12 @@ static int test_crtc(Display *dpy, void *queue, uint64_t last_msc)
 	err += for_each_crtc(dpy, __test_crtc, &test);
 	test.msc = check_msc(dpy, test.win, test.queue, test.msc);
 
+	printf("Testing each crtc, with future flips\n");
+	test.flags = FUTURE | SYNC;
+	test.msc = check_msc(dpy, test.win, test.queue, test.msc);
+	err += for_each_crtc(dpy, __test_crtc, &test);
+	test.msc = check_msc(dpy, test.win, test.queue, test.msc);
+
 	dri3_fence_free(dpy, &test.fence);
 	XSync(dpy, True);
 	err += !!_x_error_occurred;
@@ -794,8 +951,22 @@ static int has_present(Display *dpy)
 					       &error);
 	free(reply);
 	free(error);
-	if (reply == NULL)
+	if (reply == NULL) {
+		fprintf(stderr, "XFixes not supported on %s\n", DisplayString(dpy));
+		return 0;
+	}
+
+	reply = xcb_dri3_query_version_reply(c,
+					     xcb_dri3_query_version(c,
+								    XCB_DRI3_MAJOR_VERSION,
+								    XCB_DRI3_MINOR_VERSION),
+					     &error);
+	free(reply);
+	free(error);
+	if (reply == NULL) {
+		fprintf(stderr, "DRI3 not supported on %s\n", DisplayString(dpy));
 		return 0;
+	}
 
 	reply = xcb_present_query_version_reply(c,
 						xcb_present_query_version(c,
@@ -805,8 +976,10 @@ static int has_present(Display *dpy)
 
 	free(reply);
 	free(error);
-	if (reply == NULL)
+	if (reply == NULL) {
+		fprintf(stderr, "Present not supported on %s\n", DisplayString(dpy));
 		return 0;
+	}
 
 	return 1;
 }
@@ -840,6 +1013,9 @@ int main(void)
 	error += test_future(dpy, queue);
 	last_msc = check_msc(dpy, root, queue, last_msc);
 
+	error += test_accuracy(dpy, queue);
+	last_msc = check_msc(dpy, root, queue, last_msc);
+
 	error += test_crtc(dpy, queue, last_msc);
 	last_msc = check_msc(dpy, root, queue, last_msc);