Allow DRI page flipping when some CRTCs use separate scanout buffers

As long as the CRTC we're synchronizing to doesn't.

v2:
* Remove redundant checks from can_exchange which still prevented DRI2
  page flipping

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

man/radeon.man

@@ -285,7 +285,7 @@ Set the default value of the per-output 'TearFree' property, which controls
 tearing prevention using the hardware page flipping mechanism. TearFree is
 on for any CRTC associated with one or more outputs with TearFree on. Two
 separate scanout buffers need to be allocated for each CRTC with TearFree
-on. While TearFree is on for any CRTC, it currently prevents clients from using
+on. While TearFree is on for any CRTC, it may prevent clients from using
 DRI page flipping. If this option is set, the default value of the property
 is 'on' or 'off' accordingly. If this option isn't set, the default value of the
 property is

src/drmmode_display.c

@@ -3014,7 +3014,7 @@ Bool radeon_do_pageflip(ScrnInfoPtr scrn, ClientPtr client,
 	for (i = 0; i < config->num_crtc; i++) {
 		crtc = config->crtc[i];
 
-		if (!crtc->enabled)
+		if (!drmmode_crtc_can_flip(crtc))
 			continue;
 
 		flipdata->flip_count++;

src/drmmode_display.h

@@ -146,7 +146,9 @@ drmmode_crtc_can_flip(xf86CrtcPtr crtc)
     drmmode_crtc_private_ptr drmmode_crtc = crtc->driver_private;
 
     return crtc->enabled &&
-	drmmode_crtc->pending_dpms_mode == DPMSModeOn;
+	drmmode_crtc->pending_dpms_mode == DPMSModeOn &&
+	!drmmode_crtc->rotate.bo &&
+	!drmmode_crtc->scanout[drmmode_crtc->scanout_id].bo;
 }
 
 

src/radeon_dri2.c

@@ -720,18 +720,6 @@ can_exchange(ScrnInfoPtr pScrn, DrawablePtr draw,
     struct dri2_buffer_priv *back_priv = back->driverPrivate;
     PixmapPtr front_pixmap;
     PixmapPtr back_pixmap = back_priv->pixmap;
-    xf86CrtcConfigPtr xf86_config = XF86_CRTC_CONFIG_PTR(pScrn);
-    int i;
-
-    for (i = 0; i < xf86_config->num_crtc; i++) {
-	xf86CrtcPtr crtc = xf86_config->crtc[i];
-	drmmode_crtc_private_ptr drmmode_crtc = crtc->driver_private;
-
-	if (crtc->enabled &&
-	    (crtc->rotatedData ||
-	     drmmode_crtc->scanout[drmmode_crtc->scanout_id].bo))
-	    return FALSE;
-    }
 
     if (!update_front(draw, front))
 	return FALSE;
@@ -754,9 +742,10 @@ can_exchange(ScrnInfoPtr pScrn, DrawablePtr draw,
 }
 
 static Bool
-can_flip(ScrnInfoPtr pScrn, DrawablePtr draw,
+can_flip(xf86CrtcPtr crtc, DrawablePtr draw,
 	 DRI2BufferPtr front, DRI2BufferPtr back)
 {
+    ScrnInfoPtr pScrn = crtc->scrn;
     RADEONInfoPtr info = RADEONPTR(pScrn);
     xf86CrtcConfigPtr config = XF86_CRTC_CONFIG_PTR(pScrn);
     int num_crtcs_on;
@@ -771,15 +760,10 @@ can_flip(ScrnInfoPtr pScrn, DrawablePtr draw,
 	return FALSE;
 
     for (i = 0, num_crtcs_on = 0; i < config->num_crtc; i++) {
-	xf86CrtcPtr crtc = config->crtc[i];
-	drmmode_crtc_private_ptr drmmode_crtc = crtc->driver_private;
-
-	if (!drmmode_crtc || drmmode_crtc->rotate.bo ||
-	    drmmode_crtc->scanout[drmmode_crtc->scanout_id].bo)
-	    return FALSE;
-
-	if (drmmode_crtc_can_flip(crtc))
+	if (drmmode_crtc_can_flip(config->crtc[i]))
 	    num_crtcs_on++;
+	else if (config->crtc[i] == crtc)
+	    return FALSE;
     }
 
     return num_crtcs_on > 0 && can_exchange(pScrn, draw, front, back);
@@ -859,7 +843,7 @@ static void radeon_dri2_frame_event_handler(xf86CrtcPtr crtc, uint32_t seq,
 
     switch (event->type) {
     case DRI2_FLIP:
-	if (can_flip(scrn, drawable, event->front, event->back) &&
+	if (can_flip(crtc, drawable, event->front, event->back) &&
 	    radeon_dri2_schedule_flip(crtc,
 				      event->client,
 				      drawable,
@@ -1352,7 +1336,7 @@ static int radeon_dri2_schedule_swap(ClientPtr client, DrawablePtr draw,
     current_msc &= 0xffffffff;
 
     /* Flips need to be submitted one frame before */
-    if (can_flip(scrn, draw, front, back)) {
+    if (can_flip(crtc, draw, front, back)) {
 	swap_info->type = DRI2_FLIP;
 	flip = 1;
     }

src/radeon_present.c

@@ -243,14 +243,7 @@ radeon_present_check_unflip(ScrnInfoPtr scrn)
 	return FALSE;
 
     for (i = 0, num_crtcs_on = 0; i < config->num_crtc; i++) {
-	xf86CrtcPtr crtc = config->crtc[i];
-	drmmode_crtc_private_ptr drmmode_crtc = crtc->driver_private;
-
-	if (!drmmode_crtc || drmmode_crtc->rotate.bo ||
-	    drmmode_crtc->scanout[drmmode_crtc->scanout_id].bo)
-	    return FALSE;
-
-	if (drmmode_crtc_can_flip(crtc))
+	if (drmmode_crtc_can_flip(config->crtc[i]))
 	    num_crtcs_on++;
     }
 
@@ -286,6 +279,9 @@ radeon_present_check_flip(RRCrtcPtr crtc, WindowPtr window, PixmapPtr pixmap,
 	radeon_present_get_pixmap_tiling_flags(info, screen_pixmap))
 	return FALSE;
 
+    if (!drmmode_crtc_can_flip(crtc->devPrivate))
+	return FALSE;
+
     return radeon_present_check_unflip(scrn);
 }