dri2: Fix drmWaitVblank on multi-x-screen configs.

Old mapping of xf86Crtc -> display head index was
too simple and only worked on a single x-screen config.

Introduce a new helper function drmmode_hw_head_index()
which returns proper mapping also for multi x-screens per
gpu and ZaphodHeads setups and other non-standard multi-
display configurations.

Tested on triple-head setup with various ZaphodHead and
server layout combos.

This helper will be also needed for dri3/present code.

Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>

4 files changed, 33 insertions, 12 deletions

diff --git a/src/drmmode_display.c b/src/drmmode_display.c
index 45225ad..501440a 100644
--- a/src/drmmode_display.c
+++ b/src/drmmode_display.c
@@ -59,6 +59,7 @@ typedef struct {
 typedef struct {
     drmmode_ptr drmmode;
     drmModeCrtcPtr mode_crtc;
+    int hw_crtc_index;
     struct nouveau_bo *cursor;
     struct nouveau_bo *rotate_bo;
     int rotate_pitch;
@@ -112,12 +113,19 @@ drmmode_pixmap(PixmapPtr ppix)
 }
 
 int
-drmmode_head(xf86CrtcPtr crtc)
+drmmode_crtc(xf86CrtcPtr crtc)
 {
 	drmmode_crtc_private_ptr drmmode_crtc = crtc->driver_private;
 	return drmmode_crtc->mode_crtc->crtc_id;
 }
 
+int
+drmmode_head(xf86CrtcPtr crtc)
+{
+	drmmode_crtc_private_ptr drmmode_crtc = crtc->driver_private;
+	return drmmode_crtc->hw_crtc_index;
+}
+
 void
 drmmode_swap(ScrnInfoPtr scrn, uint32_t next, uint32_t *prev)
 {
@@ -754,6 +762,7 @@ drmmode_crtc_init(ScrnInfoPtr pScrn, drmmode_ptr drmmode, int num)
 	drmmode_crtc->mode_crtc = drmModeGetCrtc(drmmode->fd,
 						 drmmode->mode_res->crtcs[num]);
 	drmmode_crtc->drmmode = drmmode;
+	drmmode_crtc->hw_crtc_index = num;
 
 	ret = nouveau_bo_new(pNv->dev, NOUVEAU_BO_GART | NOUVEAU_BO_MAP, 0,
 			     64*64*4, NULL, &drmmode_crtc->cursor);
diff --git a/src/nouveau_dri2.c b/src/nouveau_dri2.c
index 7446122..cc16cb1 100644
--- a/src/nouveau_dri2.c
+++ b/src/nouveau_dri2.c
@@ -466,7 +466,7 @@ dri2_page_flip(DrawablePtr draw, PixmapPtr back, void *priv,
 	flipdata->fd = pNv->dev->fd;
 
 	for (i = 0; i < config->num_crtc; i++) {
-		int head = drmmode_head(config->crtc[i]);
+		int head = drmmode_crtc(config->crtc[i]);
 		void *token;
 
 		if (!config->crtc[i]->enabled)
@@ -565,6 +565,7 @@ nouveau_wait_vblank(DrawablePtr draw, int type, CARD64 msc,
 		    CARD64 *pmsc, CARD64 *pust, void *data)
 {
 	ScrnInfoPtr scrn = xf86ScreenToScrn(draw->pScreen);
+	xf86CrtcConfigPtr config = XF86_CRTC_CONFIG_PTR(scrn);
 	NVPtr pNv = NVPTR(scrn);
 	int crtcs = nv_window_belongs_to_crtc(scrn, draw->x, draw->y,
 					      draw->width, draw->height);
@@ -572,6 +573,16 @@ nouveau_wait_vblank(DrawablePtr draw, int type, CARD64 msc,
 	struct dri2_vblank *event = NULL;
 	void *token = NULL;
 	int ret;
+	int head;
+
+	/* Select crtc with smallest index from bitmask of crtcs */
+	crtcs = ffs(crtcs) - 1;
+
+	if (crtcs < 0) {
+		xf86DrvMsg(scrn->scrnIndex, X_WARNING,
+				   "Wait for VBlank failed: No valid crtc for drawable.\n");
+		return -EINVAL;
+	}
 
 	if (type & DRM_VBLANK_EVENT) {
 		event = drmmode_event_queue(scrn, ++dri2_sequence,
@@ -584,20 +595,20 @@ nouveau_wait_vblank(DrawablePtr draw, int type, CARD64 msc,
 		event->s = data;
 	}
 
-	/* Select crtc with smallest index from bitmask of crtcs */
-	crtcs = ffs(crtcs) - 1;
+	/* Map xf86CrtcPtr to drmWaitVBlank compatible display head index. */
+	head = drmmode_head(config->crtc[crtcs]);
 
-	if (crtcs == 1)
+	if (head == 1)
 		type |= DRM_VBLANK_SECONDARY;
-	else if (crtcs > 1)
+	else if (head > 1)
 #ifdef DRM_VBLANK_HIGH_CRTC_SHIFT
-		type |= (crtcs << DRM_VBLANK_HIGH_CRTC_SHIFT) &
+		type |= (head << DRM_VBLANK_HIGH_CRTC_SHIFT) &
 				DRM_VBLANK_HIGH_CRTC_MASK;
 #else
 	xf86DrvMsg(scrn->scrnIndex, X_WARNING,
 			   "Wait for VBlank failed: Called for CRTC %d > 1, but "
 			   "DRM_VBLANK_HIGH_CRTC_SHIFT not defined at build time.\n",
-			   crtcs);
+			   head);
 #endif
 
 	vbl.request.type = type;
diff --git a/src/nouveau_present.c b/src/nouveau_present.c
index 38f2cac..05cd518 100644
--- a/src/nouveau_present.c
+++ b/src/nouveau_present.c
@@ -250,18 +250,18 @@ nouveau_present_flip_exec(ScrnInfoPtr scrn, uint64_t event_id, int sync,
 
 			for (i = 0; i < config->num_crtc; i++) {
 				int type = vsync ? 0 : DRM_MODE_PAGE_FLIP_ASYNC;
-				int head = drmmode_head(config->crtc[i]);
+				int crtc = drmmode_crtc(config->crtc[i]);
 				void *user = NULL;
 
 				if (!config->crtc[i]->enabled)
 					continue;
 
-				if (token && ((head == sync) || (i == last))) {
+				if (token && ((crtc == sync) || (i == last))) {
 					type |= DRM_MODE_PAGE_FLIP_EVENT;
 					user  = token;
 				}
 
-				ret = drmModePageFlip(pNv->dev->fd, head,
+				ret = drmModePageFlip(pNv->dev->fd, crtc,
 						      next_fb, type, user);
 				if (ret == 0 && user) {
 					token = NULL;
@@ -288,7 +288,7 @@ nouveau_present_flip_next(RRCrtcPtr rrcrtc, uint64_t event_id,
 {
 	xf86CrtcPtr crtc = rrcrtc->devPrivate;
 	ScrnInfoPtr scrn = crtc->scrn;
-	return nouveau_present_flip_exec(scrn, event_id, drmmode_head(crtc),
+	return nouveau_present_flip_exec(scrn, event_id, drmmode_crtc(crtc),
 					 target_msc, pixmap, vsync);
 }
 
diff --git a/src/nv_proto.h b/src/nv_proto.h
index c076461..27354e0 100644
--- a/src/nv_proto.h
+++ b/src/nv_proto.h
@@ -12,6 +12,7 @@ Bool drmmode_page_flip(DrawablePtr draw, PixmapPtr back, void *priv,
 void drmmode_screen_init(ScreenPtr pScreen);
 void drmmode_screen_fini(ScreenPtr pScreen);
 
+int  drmmode_crtc(xf86CrtcPtr crtc);
 int  drmmode_head(xf86CrtcPtr crtc);
 void drmmode_swap(ScrnInfoPtr, uint32_t, uint32_t *);