drm/vmwgfx: Add max surface memory param

Userspace uses this to workaround overcommit issues
by flushing the command stream early.
Signed-off-by: Jakob Bornecrantz <jakob@vmware.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>

drivers/gpu/drm/vmwgfx/vmwgfx_ioctl.c

@@ -68,6 +68,9 @@ int vmw_getparam_ioctl(struct drm_device *dev, void *data,
 				  SVGA_FIFO_3D_HWVERSION));
 		break;
 	}
+	case DRM_VMW_PARAM_MAX_SURF_MEMORY:
+		param->value = dev_priv->memory_size;
+		break;
 	default:
 		DRM_ERROR("Illegal vmwgfx get param request: %d\n",
 			  param->param);

include/uapi/drm/vmwgfx_drm.h

@@ -75,6 +75,7 @@
 #define DRM_VMW_PARAM_FIFO_CAPS        4
 #define DRM_VMW_PARAM_MAX_FB_SIZE      5
 #define DRM_VMW_PARAM_FIFO_HW_VERSION  6
+#define DRM_VMW_PARAM_MAX_SURF_MEMORY  7
 
 /**
  * struct drm_vmw_getparam_arg