drm/udl: Store active framebuffer in device structure

The framebuffer's 'active_16' flag signals which framebuffer to flush
to device memory. Moving the 'active_16' state from struct udl_framebuffer
into struct udl_device prepares for using the generic GEM framebuffer.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191114141025.32198-4-tzimmermann@suse.de

drivers/gpu/drm/udl/udl_drv.h

@@ -53,6 +53,10 @@ struct udl_device {
 	struct usb_device *udev;
 	struct drm_crtc *crtc;
 
+	/* active framebuffer on the 16-bit channel */
+	const struct drm_framebuffer *active_fb_16;
+	spinlock_t active_fb_16_lock;
+
 	struct mutex gem_lock;
 
 	int sku_pixel_limit;
@@ -73,7 +77,6 @@ struct udl_device {
 struct udl_framebuffer {
 	struct drm_framebuffer base;
 	struct drm_gem_shmem_object *shmem;
-	bool active_16; /* active on the 16-bit channel */
 };
 
 #define to_udl_fb(x) container_of(x, struct udl_framebuffer, base)

drivers/gpu/drm/udl/udl_fb.c

@@ -78,8 +78,12 @@ int udl_handle_damage(struct udl_framebuffer *fb, int x, int y,
 	BUG_ON(!is_power_of_2(fb->base.format->cpp[0]));
 	log_bpp = __ffs(fb->base.format->cpp[0]);
 
-	if (!fb->active_16)
+	spin_lock(&udl->active_fb_16_lock);
+	if (udl->active_fb_16 != &fb->base) {
+		spin_unlock(&udl->active_fb_16_lock);
 		return 0;
+	}
+	spin_unlock(&udl->active_fb_16_lock);
 
 	vaddr = drm_gem_shmem_vmap(&fb->shmem->base);
 	if (IS_ERR(vaddr)) {
@@ -153,14 +157,19 @@ static int udl_user_framebuffer_dirty(struct drm_framebuffer *fb,
 				      unsigned num_clips)
 {
 	struct udl_framebuffer *ufb = to_udl_fb(fb);
+	struct udl_device *udl = fb->dev->dev_private;
 	struct dma_buf_attachment *import_attach;
 	int i;
 	int ret = 0;
 
 	drm_modeset_lock_all(fb->dev);
 
-	if (!ufb->active_16)
+	spin_lock(&udl->active_fb_16_lock);
+	if (udl->active_fb_16 != fb) {
+		spin_unlock(&udl->active_fb_16_lock);
 		goto unlock;
+	}
+	spin_unlock(&udl->active_fb_16_lock);
 
 	import_attach = ufb->shmem->base.import_attach;
 

drivers/gpu/drm/udl/udl_main.c

@@ -317,6 +317,9 @@ int udl_init(struct udl_device *udl)
 
 	DRM_DEBUG("\n");
 
+	udl->active_fb_16 = NULL;
+	spin_lock_init(&udl->active_fb_16_lock);
+
 	mutex_init(&udl->gem_lock);
 
 	if (!udl_parse_vendor_descriptor(dev, udl->udev)) {

drivers/gpu/drm/udl/udl_modeset.c

@@ -332,11 +332,9 @@ static int udl_crtc_mode_set(struct drm_crtc *crtc,
 
 	wrptr = udl_dummy_render(wrptr);
 
-	if (old_fb) {
-		struct udl_framebuffer *uold_fb = to_udl_fb(old_fb);
-		uold_fb->active_16 = false;
-	}
-	ufb->active_16 = true;
+	spin_lock(&udl->active_fb_16_lock);
+	udl->active_fb_16 = &ufb->base;
+	spin_unlock(&udl->active_fb_16_lock);
 	udl->mode_buf_len = wrptr - buf;
 
 	/* damage all of it */
@@ -364,13 +362,11 @@ static int udl_crtc_page_flip(struct drm_crtc *crtc,
 {
 	struct udl_framebuffer *ufb = to_udl_fb(fb);
 	struct drm_device *dev = crtc->dev;
+	struct udl_device *udl = dev->dev_private;
 
-	struct drm_framebuffer *old_fb = crtc->primary->fb;
-	if (old_fb) {
-		struct udl_framebuffer *uold_fb = to_udl_fb(old_fb);
-		uold_fb->active_16 = false;
-	}
-	ufb->active_16 = true;
+	spin_lock(&udl->active_fb_16_lock);
+	udl->active_fb_16 = fb;
+	spin_unlock(&udl->active_fb_16_lock);
 
 	udl_handle_damage(ufb, 0, 0, fb->width, fb->height);