drm/nv04/disp: fix framebuffer pin refcounting

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/dispnv04/crtc.c

@@ -606,6 +606,24 @@ nv_crtc_mode_set_regs(struct drm_crtc *crtc, struct drm_display_mode * mode)
 	regp->ramdac_a34 = 0x1;
 }
 
+static int
+nv_crtc_swap_fbs(struct drm_crtc *crtc, struct drm_framebuffer *old_fb)
+{
+	struct nv04_display *disp = nv04_display(crtc->dev);
+	struct nouveau_framebuffer *nvfb = nouveau_framebuffer(crtc->fb);
+	struct nouveau_crtc *nv_crtc = nouveau_crtc(crtc);
+	int ret;
+
+	ret = nouveau_bo_pin(nvfb->nvbo, TTM_PL_FLAG_VRAM);
+	if (ret == 0) {
+		if (disp->image[nv_crtc->index])
+			nouveau_bo_unpin(disp->image[nv_crtc->index]);
+		nouveau_bo_ref(nvfb->nvbo, &disp->image[nv_crtc->index]);
+	}
+
+	return ret;
+}
+
 /**
  * Sets up registers for the given mode/adjusted_mode pair.
  *
@@ -622,10 +640,15 @@ nv_crtc_mode_set(struct drm_crtc *crtc, struct drm_display_mode *mode,
 	struct drm_device *dev = crtc->dev;
 	struct nouveau_crtc *nv_crtc = nouveau_crtc(crtc);
 	struct nouveau_drm *drm = nouveau_drm(dev);
+	int ret;
 
 	NV_DEBUG(drm, "CTRC mode on CRTC %d:\n", nv_crtc->index);
 	drm_mode_debug_printmodeline(adjusted_mode);
 
+	ret = nv_crtc_swap_fbs(crtc, old_fb);
+	if (ret)
+		return ret;
+
 	/* unlock must come after turning off FP_TG_CONTROL in output_prepare */
 	nv_lock_vga_crtc_shadow(dev, nv_crtc->index, -1);
 
@@ -722,13 +745,18 @@ static void nv_crtc_commit(struct drm_crtc *crtc)
 
 static void nv_crtc_destroy(struct drm_crtc *crtc)
 {
+	struct nv04_display *disp = nv04_display(crtc->dev);
 	struct nouveau_crtc *nv_crtc = nouveau_crtc(crtc);
 
 	if (!nv_crtc)
 		return;
 
 	drm_crtc_cleanup(crtc);
 
+	if (disp->image[nv_crtc->index])
+		nouveau_bo_unpin(disp->image[nv_crtc->index]);
+	nouveau_bo_ref(NULL, &disp->image[nv_crtc->index]);
+
 	nouveau_bo_unmap(nv_crtc->cursor.nvbo);
 	nouveau_bo_unpin(nv_crtc->cursor.nvbo);
 	nouveau_bo_ref(NULL, &nv_crtc->cursor.nvbo);
@@ -753,6 +781,16 @@ nv_crtc_gamma_load(struct drm_crtc *crtc)
 	nouveau_hw_load_state_palette(dev, nv_crtc->index, &nv04_display(dev)->mode_reg);
 }
 
+static void
+nv_crtc_disable(struct drm_crtc *crtc)
+{
+	struct nv04_display *disp = nv04_display(crtc->dev);
+	struct nouveau_crtc *nv_crtc = nouveau_crtc(crtc);
+	if (disp->image[nv_crtc->index])
+		nouveau_bo_unpin(disp->image[nv_crtc->index]);
+	nouveau_bo_ref(NULL, &disp->image[nv_crtc->index]);
+}
+
 static void
 nv_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b, uint32_t start,
 		  uint32_t size)
@@ -791,7 +829,6 @@ nv04_crtc_do_mode_set_base(struct drm_crtc *crtc,
 	struct drm_framebuffer *drm_fb;
 	struct nouveau_framebuffer *fb;
 	int arb_burst, arb_lwm;
-	int ret;
 
 	NV_DEBUG(drm, "index %d\n", nv_crtc->index);
 
@@ -801,28 +838,15 @@ nv04_crtc_do_mode_set_base(struct drm_crtc *crtc,
 		return 0;
 	}
 
-
 	/* If atomic, we want to switch to the fb we were passed, so
-	 * now we update pointers to do that.  (We don't pin; just
-	 * assume we're already pinned and update the base address.)
+	 * now we update pointers to do that.
 	 */
 	if (atomic) {
 		drm_fb = passed_fb;
 		fb = nouveau_framebuffer(passed_fb);
 	} else {
 		drm_fb = crtc->fb;
 		fb = nouveau_framebuffer(crtc->fb);
-		/* If not atomic, we can go ahead and pin, and unpin the
-		 * old fb we were passed.
-		 */
-		ret = nouveau_bo_pin(fb->nvbo, TTM_PL_FLAG_VRAM);
-		if (ret)
-			return ret;
-
-		if (passed_fb) {
-			struct nouveau_framebuffer *ofb = nouveau_framebuffer(passed_fb);
-			nouveau_bo_unpin(ofb->nvbo);
-		}
 	}
 
 	nv_crtc->fb.offset = fb->nvbo->bo.offset;
@@ -877,6 +901,9 @@ static int
 nv04_crtc_mode_set_base(struct drm_crtc *crtc, int x, int y,
 			struct drm_framebuffer *old_fb)
 {
+	int ret = nv_crtc_swap_fbs(crtc, old_fb);
+	if (ret)
+		return ret;
 	return nv04_crtc_do_mode_set_base(crtc, old_fb, x, y, false);
 }
 
@@ -1027,6 +1054,7 @@ static const struct drm_crtc_helper_funcs nv04_crtc_helper_funcs = {
 	.mode_set_base = nv04_crtc_mode_set_base,
 	.mode_set_base_atomic = nv04_crtc_mode_set_base_atomic,
 	.load_lut = nv_crtc_gamma_load,
+	.disable = nv_crtc_disable,
 };
 
 int

drivers/gpu/drm/nouveau/dispnv04/disp.h

@@ -81,6 +81,7 @@ struct nv04_display {
 	uint32_t saved_vga_font[4][16384];
 	uint32_t dac_users[4];
 	struct nouveau_object *core;
+	struct nouveau_bo *image[2];
 };
 
 static inline struct nv04_display *

drivers/gpu/drm/nouveau/nouveau_display.c

@@ -577,6 +577,9 @@ nouveau_crtc_page_flip(struct drm_crtc *crtc, struct drm_framebuffer *fb,
 		ret = nv50_display_flip_next(crtc, fb, chan, 0);
 		if (ret)
 			goto fail_unreserve;
+	} else {
+		struct nv04_display *dispnv04 = nv04_display(dev);
+		nouveau_bo_ref(new_bo, &dispnv04->image[nouveau_crtc(crtc)->index]);
 	}
 
 	ret = nouveau_page_flip_emit(chan, old_bo, new_bo, s, &fence);