vmwgfx: Switch to VGA when we drop master and vmwgfx fbdev is not active

Previously this was not done when any 3D resource was active,
since that meant disabling the fifo with all 3D state lost.
Now, if there are still 3D resources active, we use the svga hide feature.

This fixes X server VT switching with 3D enabled.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Jakob Bornecrantz <jakob@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/vmwgfx/vmwgfx_drv.c

@@ -209,7 +209,14 @@ static void vmw_release_device(struct vmw_private *dev_priv)
 	vmw_fifo_release(dev_priv, &dev_priv->fifo);
 }
 
-int vmw_3d_resource_inc(struct vmw_private *dev_priv)
+/**
+ * Increase the 3d resource refcount.
+ * If the count was prevously zero, initialize the fifo, switching to svga
+ * mode. Note that the master holds a ref as well, and may request an
+ * explicit switch to svga mode if fb is not running, using @unhide_svga.
+ */
+int vmw_3d_resource_inc(struct vmw_private *dev_priv,
+			bool unhide_svga)
 {
 	int ret = 0;
 
@@ -218,19 +225,42 @@ int vmw_3d_resource_inc(struct vmw_private *dev_priv)
 		ret = vmw_request_device(dev_priv);
 		if (unlikely(ret != 0))
 			--dev_priv->num_3d_resources;
+	} else if (unhide_svga) {
+		mutex_lock(&dev_priv->hw_mutex);
+		vmw_write(dev_priv, SVGA_REG_ENABLE,
+			  vmw_read(dev_priv, SVGA_REG_ENABLE) &
+			  ~SVGA_REG_ENABLE_HIDE);
+		mutex_unlock(&dev_priv->hw_mutex);
 	}
+
 	mutex_unlock(&dev_priv->release_mutex);
 	return ret;
 }
 
-
-void vmw_3d_resource_dec(struct vmw_private *dev_priv)
+/**
+ * Decrease the 3d resource refcount.
+ * If the count reaches zero, disable the fifo, switching to vga mode.
+ * Note that the master holds a refcount as well, and may request an
+ * explicit switch to vga mode when it releases its refcount to account
+ * for the situation of an X server vt switch to VGA with 3d resources
+ * active.
+ */
+void vmw_3d_resource_dec(struct vmw_private *dev_priv,
+			 bool hide_svga)
 {
 	int32_t n3d;
 
 	mutex_lock(&dev_priv->release_mutex);
 	if (unlikely(--dev_priv->num_3d_resources == 0))
 		vmw_release_device(dev_priv);
+	else if (hide_svga) {
+		mutex_lock(&dev_priv->hw_mutex);
+		vmw_write(dev_priv, SVGA_REG_ENABLE,
+			  vmw_read(dev_priv, SVGA_REG_ENABLE) |
+			  SVGA_REG_ENABLE_HIDE);
+		mutex_unlock(&dev_priv->hw_mutex);
+	}
+
 	n3d = (int32_t) dev_priv->num_3d_resources;
 	mutex_unlock(&dev_priv->release_mutex);
 
@@ -399,7 +429,7 @@ static int vmw_driver_load(struct drm_device *dev, unsigned long chipset)
 		goto out_no_kms;
 	vmw_overlay_init(dev_priv);
 	if (dev_priv->enable_fb) {
-		ret = vmw_3d_resource_inc(dev_priv);
+		ret = vmw_3d_resource_inc(dev_priv, false);
 		if (unlikely(ret != 0))
 			goto out_no_fifo;
 		vmw_kms_save_vga(dev_priv);
@@ -429,7 +459,7 @@ static int vmw_driver_load(struct drm_device *dev, unsigned long chipset)
 	if (dev_priv->enable_fb) {
 		vmw_fb_close(dev_priv);
 		vmw_kms_restore_vga(dev_priv);
-		vmw_3d_resource_dec(dev_priv);
+		vmw_3d_resource_dec(dev_priv, false);
 	}
 out_no_fifo:
 	vmw_overlay_close(dev_priv);
@@ -474,7 +504,7 @@ static int vmw_driver_unload(struct drm_device *dev)
 	if (dev_priv->enable_fb) {
 		vmw_fb_close(dev_priv);
 		vmw_kms_restore_vga(dev_priv);
-		vmw_3d_resource_dec(dev_priv);
+		vmw_3d_resource_dec(dev_priv, false);
 	}
 	vmw_kms_close(dev_priv);
 	vmw_overlay_close(dev_priv);
@@ -648,7 +678,7 @@ static int vmw_master_set(struct drm_device *dev,
 	int ret = 0;
 
 	if (!dev_priv->enable_fb) {
-		ret = vmw_3d_resource_inc(dev_priv);
+		ret = vmw_3d_resource_inc(dev_priv, true);
 		if (unlikely(ret != 0))
 			return ret;
 		vmw_kms_save_vga(dev_priv);
@@ -690,7 +720,7 @@ static int vmw_master_set(struct drm_device *dev,
 		vmw_write(dev_priv, SVGA_REG_TRACES, 1);
 		mutex_unlock(&dev_priv->hw_mutex);
 		vmw_kms_restore_vga(dev_priv);
-		vmw_3d_resource_dec(dev_priv);
+		vmw_3d_resource_dec(dev_priv, true);
 	}
 	return ret;
 }
@@ -728,7 +758,7 @@ static void vmw_master_drop(struct drm_device *dev,
 		vmw_write(dev_priv, SVGA_REG_TRACES, 1);
 		mutex_unlock(&dev_priv->hw_mutex);
 		vmw_kms_restore_vga(dev_priv);
-		vmw_3d_resource_dec(dev_priv);
+		vmw_3d_resource_dec(dev_priv, true);
 	}
 
 	dev_priv->active_master = &dev_priv->fbdev_master;
@@ -837,7 +867,7 @@ static int vmw_pm_prepare(struct device *kdev)
 	 */
 	dev_priv->suspended = true;
 	if (dev_priv->enable_fb)
-		vmw_3d_resource_dec(dev_priv);
+			vmw_3d_resource_dec(dev_priv, true);
 
 	if (dev_priv->num_3d_resources != 0) {
 
@@ -845,7 +875,7 @@ static int vmw_pm_prepare(struct device *kdev)
 			 "while 3D resources are active.\n");
 
 		if (dev_priv->enable_fb)
-			vmw_3d_resource_inc(dev_priv);
+			vmw_3d_resource_inc(dev_priv, true);
 		dev_priv->suspended = false;
 		return -EBUSY;
 	}
@@ -864,7 +894,7 @@ static void vmw_pm_complete(struct device *kdev)
 	 * start fifo.
 	 */
 	if (dev_priv->enable_fb)
-		vmw_3d_resource_inc(dev_priv);
+			vmw_3d_resource_inc(dev_priv, false);
 
 	dev_priv->suspended = false;
 }

drivers/gpu/drm/vmwgfx/vmwgfx_drv.h

@@ -319,8 +319,8 @@ static inline uint32_t vmw_read(struct vmw_private *dev_priv,
 	return val;
 }
 
-int vmw_3d_resource_inc(struct vmw_private *dev_priv);
-void vmw_3d_resource_dec(struct vmw_private *dev_priv);
+int vmw_3d_resource_inc(struct vmw_private *dev_priv, bool unhide_svga);
+void vmw_3d_resource_dec(struct vmw_private *dev_priv, bool hide_svga);
 
 /**
  * GMR utilities - vmwgfx_gmr.c

drivers/gpu/drm/vmwgfx/vmwgfx_resource.c

@@ -211,7 +211,7 @@ static void vmw_hw_context_destroy(struct vmw_resource *res)
 	cmd->body.cid = cpu_to_le32(res->id);
 
 	vmw_fifo_commit(dev_priv, sizeof(*cmd));
-	vmw_3d_resource_dec(dev_priv);
+	vmw_3d_resource_dec(dev_priv, false);
 }
 
 static int vmw_context_init(struct vmw_private *dev_priv,
@@ -248,7 +248,7 @@ static int vmw_context_init(struct vmw_private *dev_priv,
 	cmd->body.cid = cpu_to_le32(res->id);
 
 	vmw_fifo_commit(dev_priv, sizeof(*cmd));
-	(void) vmw_3d_resource_inc(dev_priv);
+	(void) vmw_3d_resource_inc(dev_priv, false);
 	vmw_resource_activate(res, vmw_hw_context_destroy);
 	return 0;
 }
@@ -411,7 +411,7 @@ static void vmw_hw_surface_destroy(struct vmw_resource *res)
 	cmd->body.sid = cpu_to_le32(res->id);
 
 	vmw_fifo_commit(dev_priv, sizeof(*cmd));
-	vmw_3d_resource_dec(dev_priv);
+	vmw_3d_resource_dec(dev_priv, false);
 }
 
 void vmw_surface_res_free(struct vmw_resource *res)
@@ -479,7 +479,7 @@ int vmw_surface_init(struct vmw_private *dev_priv,
 	}
 
 	vmw_fifo_commit(dev_priv, submit_size);
-	(void) vmw_3d_resource_inc(dev_priv);
+	(void) vmw_3d_resource_inc(dev_priv, false);
 	vmw_resource_activate(res, vmw_hw_surface_destroy);
 	return 0;
 }