drm/vmwgfx: Support older hardware.

V2: Fix a couple of typos.

Signed-off-by: Jakob Bornecrantz <jakob@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

6 files changed, 148 insertions, 107 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index 0c9c0811f42d..bdd87dc9e7b1 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -318,6 +318,15 @@ static int vmw_driver_load(struct drm_device *dev, unsigned long chipset)
 		goto out_err3;
 	}
 
+	/* Need mmio memory to check for fifo pitchlock cap. */
+	if (!(dev_priv->capabilities & SVGA_CAP_DISPLAY_TOPOLOGY) &&
+	    !(dev_priv->capabilities & SVGA_CAP_PITCHLOCK) &&
+	    !vmw_fifo_have_pitchlock(dev_priv)) {
+		ret = -ENOSYS;
+		DRM_ERROR("Hardware has no pitchlock\n");
+		goto out_err4;
+	}
+
 	dev_priv->tdev = ttm_object_device_init
 	    (dev_priv->mem_global_ref.object, 12);
 
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
index 9a0a82b41c3e..1341adef408d 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
@@ -187,6 +187,7 @@ struct vmw_private {
 	uint32_t vga_red_mask;
 	uint32_t vga_blue_mask;
 	uint32_t vga_green_mask;
+	uint32_t vga_pitchlock;
 
 	/*
 	 * Framebuffer info.
@@ -401,6 +402,7 @@ extern int vmw_fifo_send_fence(struct vmw_private *dev_priv,
 extern void vmw_fifo_ping_host(struct vmw_private *dev_priv, uint32_t reason);
 extern int vmw_fifo_mmap(struct file *filp, struct vm_area_struct *vma);
 extern bool vmw_fifo_have_3d(struct vmw_private *dev_priv);
+extern bool vmw_fifo_have_pitchlock(struct vmw_private *dev_priv);
 
 /**
  * TTM glue - vmwgfx_ttm_glue.c
@@ -491,6 +493,9 @@ void vmw_kms_cursor_snoop(struct vmw_surface *srf,
 			  struct ttm_object_file *tfile,
 			  struct ttm_buffer_object *bo,
 			  SVGA3dCmdHeader *header);
+void vmw_kms_write_svga(struct vmw_private *vmw_priv,
+			unsigned width, unsigned height, unsigned pitch,
+			unsigned bbp, unsigned depth);
 
 /**
  * Overlay control - vmwgfx_overlay.c
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
index 7421aaad8d09..fb66e62b8e2c 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
@@ -132,16 +132,14 @@ static int vmw_fb_check_var(struct fb_var_screeninfo *var,
 		return -EINVAL;
 	}
 
-	/* without multimon its hard to resize */
-	if (!(vmw_priv->capabilities & SVGA_CAP_MULTIMON) &&
-	    (var->xres != par->max_width ||
-	     var->yres != par->max_height)) {
-		DRM_ERROR("Tried to resize, but we don't have multimon\n");
+	if (!(vmw_priv->capabilities & SVGA_CAP_DISPLAY_TOPOLOGY) &&
+	    (var->xoffset != 0 || var->yoffset != 0)) {
+		DRM_ERROR("Can not handle panning without display topology\n");
 		return -EINVAL;
 	}
 
-	if (var->xres > par->max_width ||
-	    var->yres > par->max_height) {
+	if ((var->xoffset + var->xres) > par->max_width ||
+	    (var->yoffset + var->yres) > par->max_height) {
 		DRM_ERROR("Requested geom can not fit in framebuffer\n");
 		return -EINVAL;
 	}
@@ -154,8 +152,8 @@ static int vmw_fb_set_par(struct fb_info *info)
 	struct vmw_fb_par *par = info->par;
 	struct vmw_private *vmw_priv = par->vmw_priv;
 
-	if (vmw_priv->capabilities & SVGA_CAP_MULTIMON) {
-		vmw_write(vmw_priv, SVGA_REG_NUM_GUEST_DISPLAYS, 1);
+	if (vmw_priv->capabilities & SVGA_CAP_DISPLAY_TOPOLOGY) {
+		vmw_write(vmw_priv, SVGA_REG_ENABLE, 0);
 		vmw_write(vmw_priv, SVGA_REG_DISPLAY_ID, 0);
 		vmw_write(vmw_priv, SVGA_REG_DISPLAY_IS_PRIMARY, true);
 		vmw_write(vmw_priv, SVGA_REG_DISPLAY_POSITION_X, 0);
@@ -164,18 +162,11 @@ static int vmw_fb_set_par(struct fb_info *info)
 		vmw_write(vmw_priv, SVGA_REG_DISPLAY_HEIGHT, 0);
 		vmw_write(vmw_priv, SVGA_REG_DISPLAY_ID, SVGA_ID_INVALID);
 
-		vmw_write(vmw_priv, SVGA_REG_ENABLE, 1);
-		vmw_write(vmw_priv, SVGA_REG_WIDTH, par->max_width);
-		vmw_write(vmw_priv, SVGA_REG_HEIGHT, par->max_height);
-		vmw_write(vmw_priv, SVGA_REG_BITS_PER_PIXEL, par->bpp);
-		vmw_write(vmw_priv, SVGA_REG_DEPTH, par->depth);
-		vmw_write(vmw_priv, SVGA_REG_RED_MASK, 0x00ff0000);
-		vmw_write(vmw_priv, SVGA_REG_GREEN_MASK, 0x0000ff00);
-		vmw_write(vmw_priv, SVGA_REG_BLUE_MASK, 0x000000ff);
+		vmw_kms_write_svga(vmw_priv, info->var.xres, info->var.yres,
+				   info->fix.line_length,
+				   par->bpp, par->depth);
 
 		/* TODO check if pitch and offset changes */
-
-		vmw_write(vmw_priv, SVGA_REG_NUM_GUEST_DISPLAYS, 1);
 		vmw_write(vmw_priv, SVGA_REG_DISPLAY_ID, 0);
 		vmw_write(vmw_priv, SVGA_REG_DISPLAY_IS_PRIMARY, true);
 		vmw_write(vmw_priv, SVGA_REG_DISPLAY_POSITION_X, info->var.xoffset);
@@ -183,13 +174,22 @@ static int vmw_fb_set_par(struct fb_info *info)
 		vmw_write(vmw_priv, SVGA_REG_DISPLAY_WIDTH, info->var.xres);
 		vmw_write(vmw_priv, SVGA_REG_DISPLAY_HEIGHT, info->var.yres);
 		vmw_write(vmw_priv, SVGA_REG_DISPLAY_ID, SVGA_ID_INVALID);
+		vmw_write(vmw_priv, SVGA_REG_NUM_GUEST_DISPLAYS, 1);
+		vmw_write(vmw_priv, SVGA_REG_ENABLE, 1);
 	} else {
-		vmw_write(vmw_priv, SVGA_REG_WIDTH, info->var.xres);
-		vmw_write(vmw_priv, SVGA_REG_HEIGHT, info->var.yres);
+		vmw_write(vmw_priv, SVGA_REG_ENABLE, 0);
+		vmw_kms_write_svga(vmw_priv, info->var.xres, info->var.yres,
+				   info->fix.line_length,
+				   par->bpp, par->depth);
+		vmw_write(vmw_priv, SVGA_REG_ENABLE, 1);
 
-		/* TODO check if pitch and offset changes */
 	}
 
+	/* This is really helpful since if this fails the user
+	 * can probably not see anything on the screen.
+	 */
+	WARN_ON(vmw_read(vmw_priv, SVGA_REG_FB_OFFSET) != 0);
+
 	return 0;
 }
 
@@ -416,48 +416,23 @@ int vmw_fb_init(struct vmw_private *vmw_priv)
 	unsigned fb_bbp, fb_depth, fb_offset, fb_pitch, fb_size;
 	int ret;
 
+	/* XXX These shouldn't be hardcoded. */
 	initial_width = 800;
 	initial_height = 600;
 
 	fb_bbp = 32;
 	fb_depth = 24;
 
-	if (vmw_priv->capabilities & SVGA_CAP_MULTIMON) {
-		fb_width = min(vmw_priv->fb_max_width, (unsigned)2048);
-		fb_height = min(vmw_priv->fb_max_height, (unsigned)2048);
-	} else {
-		fb_width = min(vmw_priv->fb_max_width, initial_width);
-		fb_height = min(vmw_priv->fb_max_height, initial_height);
-	}
+	/* XXX As shouldn't these be as well. */
+	fb_width = min(vmw_priv->fb_max_width, (unsigned)2048);
+	fb_height = min(vmw_priv->fb_max_height, (unsigned)2048);
 
 	initial_width = min(fb_width, initial_width);
 	initial_height = min(fb_height, initial_height);
 
-	vmw_write(vmw_priv, SVGA_REG_WIDTH, fb_width);
-	vmw_write(vmw_priv, SVGA_REG_HEIGHT, fb_height);
-	vmw_write(vmw_priv, SVGA_REG_BITS_PER_PIXEL, fb_bbp);
-	vmw_write(vmw_priv, SVGA_REG_DEPTH, fb_depth);
-	vmw_write(vmw_priv, SVGA_REG_RED_MASK, 0x00ff0000);
-	vmw_write(vmw_priv, SVGA_REG_GREEN_MASK, 0x0000ff00);
-	vmw_write(vmw_priv, SVGA_REG_BLUE_MASK, 0x000000ff);
-
-	fb_size = vmw_read(vmw_priv, SVGA_REG_FB_SIZE);
+	fb_pitch = fb_width * fb_bbp / 8;
+	fb_size = fb_pitch * fb_height;
 	fb_offset = vmw_read(vmw_priv, SVGA_REG_FB_OFFSET);
-	fb_pitch = vmw_read(vmw_priv, SVGA_REG_BYTES_PER_LINE);
-
-	DRM_DEBUG("width  %u\n", vmw_read(vmw_priv, SVGA_REG_MAX_WIDTH));
-	DRM_DEBUG("height %u\n", vmw_read(vmw_priv, SVGA_REG_MAX_HEIGHT));
-	DRM_DEBUG("width  %u\n", vmw_read(vmw_priv, SVGA_REG_WIDTH));
-	DRM_DEBUG("height %u\n", vmw_read(vmw_priv, SVGA_REG_HEIGHT));
-	DRM_DEBUG("bpp    %u\n", vmw_read(vmw_priv, SVGA_REG_BITS_PER_PIXEL));
-	DRM_DEBUG("depth  %u\n", vmw_read(vmw_priv, SVGA_REG_DEPTH));
-	DRM_DEBUG("bpl    %u\n", vmw_read(vmw_priv, SVGA_REG_BYTES_PER_LINE));
-	DRM_DEBUG("r mask %08x\n", vmw_read(vmw_priv, SVGA_REG_RED_MASK));
-	DRM_DEBUG("g mask %08x\n", vmw_read(vmw_priv, SVGA_REG_GREEN_MASK));
-	DRM_DEBUG("b mask %08x\n", vmw_read(vmw_priv, SVGA_REG_BLUE_MASK));
-	DRM_DEBUG("fb_offset 0x%08x\n", fb_offset);
-	DRM_DEBUG("fb_pitch  %u\n", fb_pitch);
-	DRM_DEBUG("fb_size   %u kiB\n", fb_size / 1024);
 
 	info = framebuffer_alloc(sizeof(*par), device);
 	if (!info)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c
index a8e5445f94ec..e6a1eb7ea954 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fifo.c
@@ -34,6 +34,9 @@ bool vmw_fifo_have_3d(struct vmw_private *dev_priv)
 	__le32 __iomem *fifo_mem = dev_priv->mmio_virt;
 	uint32_t fifo_min, hwversion;
 
+	if (!(dev_priv->capabilities & SVGA_CAP_EXTENDED_FIFO))
+		return false;
+
 	fifo_min = ioread32(fifo_mem  + SVGA_FIFO_MIN);
 	if (fifo_min <= SVGA_FIFO_3D_HWVERSION * sizeof(unsigned int))
 		return false;
@@ -48,6 +51,21 @@ bool vmw_fifo_have_3d(struct vmw_private *dev_priv)
 	return true;
 }
 
+bool vmw_fifo_have_pitchlock(struct vmw_private *dev_priv)
+{
+	__le32 __iomem *fifo_mem = dev_priv->mmio_virt;
+	uint32_t caps;
+
+	if (!(dev_priv->capabilities & SVGA_CAP_EXTENDED_FIFO))
+		return false;
+
+	caps = ioread32(fifo_mem + SVGA_FIFO_CAPABILITIES);
+	if (caps & SVGA_FIFO_CAP_PITCHLOCK)
+		return true;
+
+	return false;
+}
+
 int vmw_fifo_init(struct vmw_private *dev_priv, struct vmw_fifo_state *fifo)
 {
 	__le32 __iomem *fifo_mem = dev_priv->mmio_virt;
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index 642bcd7a1500..c748207e9e1c 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -596,31 +596,11 @@ static int vmw_framebuffer_dmabuf_pin(struct vmw_framebuffer *vfb)
 		vmw_framebuffer_to_vfbd(&vfb->base);
 	int ret;
 
+
 	vmw_overlay_pause_all(dev_priv);
 
 	ret = vmw_dmabuf_to_start_of_vram(dev_priv, vfbd->buffer);
 
-	if (dev_priv->capabilities & SVGA_CAP_MULTIMON) {
-		vmw_write(dev_priv, SVGA_REG_NUM_GUEST_DISPLAYS, 1);
-		vmw_write(dev_priv, SVGA_REG_DISPLAY_ID, 0);
-		vmw_write(dev_priv, SVGA_REG_DISPLAY_IS_PRIMARY, true);
-		vmw_write(dev_priv, SVGA_REG_DISPLAY_POSITION_X, 0);
-		vmw_write(dev_priv, SVGA_REG_DISPLAY_POSITION_Y, 0);
-		vmw_write(dev_priv, SVGA_REG_DISPLAY_WIDTH, 0);
-		vmw_write(dev_priv, SVGA_REG_DISPLAY_HEIGHT, 0);
-		vmw_write(dev_priv, SVGA_REG_DISPLAY_ID, SVGA_ID_INVALID);
-
-		vmw_write(dev_priv, SVGA_REG_ENABLE, 1);
-		vmw_write(dev_priv, SVGA_REG_WIDTH, vfb->base.width);
-		vmw_write(dev_priv, SVGA_REG_HEIGHT, vfb->base.height);
-		vmw_write(dev_priv, SVGA_REG_BITS_PER_PIXEL, vfb->base.bits_per_pixel);
-		vmw_write(dev_priv, SVGA_REG_DEPTH, vfb->base.depth);
-		vmw_write(dev_priv, SVGA_REG_RED_MASK, 0x00ff0000);
-		vmw_write(dev_priv, SVGA_REG_GREEN_MASK, 0x0000ff00);
-		vmw_write(dev_priv, SVGA_REG_BLUE_MASK, 0x000000ff);
-	} else
-		WARN_ON(true);
-
 	vmw_overlay_resume_all(dev_priv);
 
 	return 0;
@@ -668,7 +648,7 @@ int vmw_kms_new_framebuffer_dmabuf(struct vmw_private *dev_priv,
 
 	/* XXX get the first 3 from the surface info */
 	vfbd->base.base.bits_per_pixel = 32;
-	vfbd->base.base.pitch = width * 32 / 4;
+	vfbd->base.base.pitch = width * vfbd->base.base.bits_per_pixel / 8;
 	vfbd->base.base.depth = 24;
 	vfbd->base.base.width = width;
 	vfbd->base.base.height = height;
@@ -827,24 +807,25 @@ out:
 	return ret;
 }
 
-int vmw_kms_save_vga(struct vmw_private *vmw_priv)
+void vmw_kms_write_svga(struct vmw_private *vmw_priv,
+			unsigned width, unsigned height, unsigned pitch,
+			unsigned bbp, unsigned depth)
 {
-	/*
-	 * setup a single multimon monitor with the size
-	 * of 0x0, this stops the UI from resizing when we
-	 * change the framebuffer size
-	 */
-	if (vmw_priv->capabilities & SVGA_CAP_MULTIMON) {
-		vmw_write(vmw_priv, SVGA_REG_NUM_GUEST_DISPLAYS, 1);
-		vmw_write(vmw_priv, SVGA_REG_DISPLAY_ID, 0);
-		vmw_write(vmw_priv, SVGA_REG_DISPLAY_IS_PRIMARY, true);
-		vmw_write(vmw_priv, SVGA_REG_DISPLAY_POSITION_X, 0);
-		vmw_write(vmw_priv, SVGA_REG_DISPLAY_POSITION_Y, 0);
-		vmw_write(vmw_priv, SVGA_REG_DISPLAY_WIDTH, 0);
-		vmw_write(vmw_priv, SVGA_REG_DISPLAY_HEIGHT, 0);
-		vmw_write(vmw_priv, SVGA_REG_DISPLAY_ID, SVGA_ID_INVALID);
-	}
+	if (vmw_priv->capabilities & SVGA_CAP_PITCHLOCK)
+		vmw_write(vmw_priv, SVGA_REG_PITCHLOCK, pitch);
+	else if (vmw_fifo_have_pitchlock(vmw_priv))
+		iowrite32(pitch, vmw_priv->mmio_virt + SVGA_FIFO_PITCHLOCK);
+	vmw_write(vmw_priv, SVGA_REG_WIDTH, width);
+	vmw_write(vmw_priv, SVGA_REG_HEIGHT, height);
+	vmw_write(vmw_priv, SVGA_REG_BITS_PER_PIXEL, bbp);
+	vmw_write(vmw_priv, SVGA_REG_DEPTH, depth);
+	vmw_write(vmw_priv, SVGA_REG_RED_MASK, 0x00ff0000);
+	vmw_write(vmw_priv, SVGA_REG_GREEN_MASK, 0x0000ff00);
+	vmw_write(vmw_priv, SVGA_REG_BLUE_MASK, 0x000000ff);
+}
 
+int vmw_kms_save_vga(struct vmw_private *vmw_priv)
+{
 	vmw_priv->vga_width = vmw_read(vmw_priv, SVGA_REG_WIDTH);
 	vmw_priv->vga_height = vmw_read(vmw_priv, SVGA_REG_HEIGHT);
 	vmw_priv->vga_bpp = vmw_read(vmw_priv, SVGA_REG_BITS_PER_PIXEL);
@@ -853,6 +834,12 @@ int vmw_kms_save_vga(struct vmw_private *vmw_priv)
 	vmw_priv->vga_red_mask = vmw_read(vmw_priv, SVGA_REG_RED_MASK);
 	vmw_priv->vga_green_mask = vmw_read(vmw_priv, SVGA_REG_GREEN_MASK);
 	vmw_priv->vga_blue_mask = vmw_read(vmw_priv, SVGA_REG_BLUE_MASK);
+	if (vmw_priv->capabilities & SVGA_CAP_PITCHLOCK)
+		vmw_priv->vga_pitchlock =
+			vmw_read(vmw_priv, SVGA_REG_PITCHLOCK);
+	else if (vmw_fifo_have_pitchlock(vmw_priv))
+		vmw_priv->vga_pitchlock =
+			ioread32(vmw_priv->mmio_virt + SVGA_FIFO_PITCHLOCK);
 
 	return 0;
 }
@@ -867,9 +854,12 @@ int vmw_kms_restore_vga(struct vmw_private *vmw_priv)
 	vmw_write(vmw_priv, SVGA_REG_RED_MASK, vmw_priv->vga_red_mask);
 	vmw_write(vmw_priv, SVGA_REG_GREEN_MASK, vmw_priv->vga_green_mask);
 	vmw_write(vmw_priv, SVGA_REG_BLUE_MASK, vmw_priv->vga_blue_mask);
-
-	/* TODO check for multimon */
-	vmw_write(vmw_priv, SVGA_REG_NUM_GUEST_DISPLAYS, 0);
+	if (vmw_priv->capabilities & SVGA_CAP_PITCHLOCK)
+		vmw_write(vmw_priv, SVGA_REG_PITCHLOCK,
+			  vmw_priv->vga_pitchlock);
+	else if (vmw_fifo_have_pitchlock(vmw_priv))
+		iowrite32(vmw_priv->vga_pitchlock,
+			  vmw_priv->mmio_virt + SVGA_FIFO_PITCHLOCK);
 
 	return 0;
 }
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c
index fefef9012c4b..8fde9bf8be41 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c
@@ -38,6 +38,7 @@ struct vmw_legacy_display {
 	struct list_head active;
 
 	unsigned num_active;
+	unsigned last_num_active;
 
 	struct vmw_framebuffer *fb;
 };
@@ -88,12 +89,37 @@ static int vmw_ldu_commit_list(struct vmw_private *dev_priv)
 {
 	struct vmw_legacy_display *lds = dev_priv->ldu_priv;
 	struct vmw_legacy_display_unit *entry;
-	struct drm_crtc *crtc;
+	struct drm_framebuffer *fb = NULL;
+	struct drm_crtc *crtc = NULL;
 	int i = 0;
 
-	/* to stop the screen from changing size on resize */
-	vmw_write(dev_priv, SVGA_REG_NUM_GUEST_DISPLAYS, 0);
-	for (i = 0; i < lds->num_active; i++) {
+	/* If there is no display topology the host just assumes
+	 * that the guest will set the same layout as the host.
+	 */
+	if (!(dev_priv->capabilities & SVGA_CAP_DISPLAY_TOPOLOGY)) {
+		int w = 0, h = 0;
+		list_for_each_entry(entry, &lds->active, active) {
+			crtc = &entry->base.crtc;
+			w = max(w, crtc->x + crtc->mode.hdisplay);
+			h = max(h, crtc->y + crtc->mode.vdisplay);
+			i++;
+		}
+
+		if (crtc == NULL)
+			return 0;
+		fb = entry->base.crtc.fb;
+
+		vmw_write(dev_priv, SVGA_REG_ENABLE, 0);
+		vmw_kms_write_svga(dev_priv, w, h, fb->pitch,
+				   fb->bits_per_pixel, fb->depth);
+		vmw_write(dev_priv, SVGA_REG_ENABLE, 1);
+
+		return 0;
+	}
+
+	vmw_write(dev_priv, SVGA_REG_ENABLE, 0);
+
+	for (i = 0; i < lds->last_num_active; i++) {
 		vmw_write(dev_priv, SVGA_REG_DISPLAY_ID, i);
 		vmw_write(dev_priv, SVGA_REG_DISPLAY_IS_PRIMARY, !i);
 		vmw_write(dev_priv, SVGA_REG_DISPLAY_POSITION_X, 0);
@@ -103,8 +129,14 @@ static int vmw_ldu_commit_list(struct vmw_private *dev_priv)
 		vmw_write(dev_priv, SVGA_REG_DISPLAY_ID, SVGA_ID_INVALID);
 	}
 
-	/* Now set the mode */
-	vmw_write(dev_priv, SVGA_REG_NUM_GUEST_DISPLAYS, lds->num_active);
+	if (!list_empty(&lds->active)) {
+		entry = list_entry(lds->active.next, typeof(*entry), active);
+		fb = entry->base.crtc.fb;
+
+		vmw_kms_write_svga(dev_priv, fb->width, fb->height, fb->pitch,
+				   fb->bits_per_pixel, fb->depth);
+	}
+
 	i = 0;
 	list_for_each_entry(entry, &lds->active, active) {
 		crtc = &entry->base.crtc;
@@ -120,6 +152,14 @@ static int vmw_ldu_commit_list(struct vmw_private *dev_priv)
 		i++;
 	}
 
+	/* Make sure we always show something. */
+	vmw_write(dev_priv, SVGA_REG_NUM_GUEST_DISPLAYS, i ? i : 1);
+	vmw_write(dev_priv, SVGA_REG_ENABLE, 1);
+
+	BUG_ON(i != lds->num_active);
+
+	lds->last_num_active = lds->num_active;
+
 	return 0;
 }
 
@@ -491,18 +531,22 @@ int vmw_kms_init_legacy_display_system(struct vmw_private *dev_priv)
 
 	INIT_LIST_HEAD(&dev_priv->ldu_priv->active);
 	dev_priv->ldu_priv->num_active = 0;
+	dev_priv->ldu_priv->last_num_active = 0;
 	dev_priv->ldu_priv->fb = NULL;
 
 	drm_mode_create_dirty_info_property(dev_priv->dev);
 
 	vmw_ldu_init(dev_priv, 0);
-	vmw_ldu_init(dev_priv, 1);
-	vmw_ldu_init(dev_priv, 2);
-	vmw_ldu_init(dev_priv, 3);
-	vmw_ldu_init(dev_priv, 4);
-	vmw_ldu_init(dev_priv, 5);
-	vmw_ldu_init(dev_priv, 6);
-	vmw_ldu_init(dev_priv, 7);
+	/* for old hardware without multimon only enable one display */
+	if (dev_priv->capabilities & SVGA_CAP_MULTIMON) {
+		vmw_ldu_init(dev_priv, 1);
+		vmw_ldu_init(dev_priv, 2);
+		vmw_ldu_init(dev_priv, 3);
+		vmw_ldu_init(dev_priv, 4);
+		vmw_ldu_init(dev_priv, 5);
+		vmw_ldu_init(dev_priv, 6);
+		vmw_ldu_init(dev_priv, 7);
+	}
 
 	return 0;
 }