4 files changed, 18 insertions, 3 deletions
diff --git a/src/gallium/winsys/svga/drm/vmw_context.c b/src/gallium/winsys/svga/drm/vmw_context.c
index d073cd4859f..8b82a9f90d3 100644
--- a/src/gallium/winsys/svga/drm/vmw_context.c
+++ b/src/gallium/winsys/svga/drm/vmw_context.c
@@ -852,6 +852,7 @@ vmw_svga_winsys_context_create(struct svga_winsys_screen *sws)
    vswc->fctx = debug_flush_ctx_create(TRUE, VMW_DEBUG_FLUSH_STACK);
 #endif
 
+   vswc->base.force_coherent = vws->force_coherent;
    return &vswc->base;
 
 out_no_hash:
diff --git a/src/gallium/winsys/svga/drm/vmw_screen.c b/src/gallium/winsys/svga/drm/vmw_screen.c
index 56294fec60e..e3440bfd957 100644
--- a/src/gallium/winsys/svga/drm/vmw_screen.c
+++ b/src/gallium/winsys/svga/drm/vmw_screen.c
@@ -90,12 +90,12 @@ vmw_winsys_create( int fd )
    vws->device = stat_buf.st_rdev;
    vws->open_count = 1;
    vws->ioctl.drm_fd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
-   vws->base.have_gb_dma = TRUE;
-   vws->base.need_to_rebind_resources = FALSE;
-
+   vws->force_coherent = FALSE;
    if (!vmw_ioctl_init(vws))
       goto out_no_ioctl;
 
+   vws->base.have_gb_dma = !vws->force_coherent;
+   vws->base.need_to_rebind_resources = FALSE;
    vws->base.have_transfer_from_buffer_cmd = vws->base.have_vgpu10;
    vws->fence_ops = vmw_fence_ops_create(vws);
    if (!vws->fence_ops)
diff --git a/src/gallium/winsys/svga/drm/vmw_screen.h b/src/gallium/winsys/svga/drm/vmw_screen.h
index cb34fec48e7..e0b1bb33bc4 100644
--- a/src/gallium/winsys/svga/drm/vmw_screen.h
+++ b/src/gallium/winsys/svga/drm/vmw_screen.h
@@ -104,6 +104,8 @@ struct vmw_winsys_screen
 
    cnd_t cs_cond;
    mtx_t cs_mutex;
+
+   boolean force_coherent;
 };
 
 
diff --git a/src/gallium/winsys/svga/drm/vmw_screen_ioctl.c b/src/gallium/winsys/svga/drm/vmw_screen_ioctl.c
index 3b14f1d3513..c7310dc7eb4 100644
--- a/src/gallium/winsys/svga/drm/vmw_screen_ioctl.c
+++ b/src/gallium/winsys/svga/drm/vmw_screen_ioctl.c
@@ -243,6 +243,9 @@ vmw_ioctl_gb_surface_create(struct vmw_winsys_screen *vws,
       if (usage & SVGA_SURFACE_USAGE_SHARED)
          req->base.drm_surface_flags |= drm_vmw_surface_flag_shareable;
 
+      if (vws->force_coherent)
+         req->base.drm_surface_flags |= drm_vmw_surface_flag_coherent;
+
       req->base.drm_surface_flags |= drm_vmw_surface_flag_create_buffer;
       req->base.base_size.width = size.width;
       req->base.base_size.height = size.height;
@@ -969,6 +972,7 @@ vmw_ioctl_init(struct vmw_winsys_screen *vws)
    drmVersionPtr version;
    boolean drm_gb_capable;
    boolean have_drm_2_5;
+   boolean have_drm_2_16;
    const char *getenv_val;
 
    VMW_FUNC;
@@ -985,6 +989,8 @@ vmw_ioctl_init(struct vmw_winsys_screen *vws)
       (version->version_major == 2 && version->version_minor > 8);
    vws->ioctl.have_drm_2_15 = version->version_major > 2 ||
       (version->version_major == 2 && version->version_minor > 14);
+   have_drm_2_16 = version->version_major > 2 ||
+      (version->version_major == 2 && version->version_minor > 15);
 
    vws->ioctl.drm_execbuf_version = vws->ioctl.have_drm_2_9 ? 2 : 1;
 
@@ -1108,6 +1114,12 @@ vmw_ioctl_init(struct vmw_winsys_screen *vws)
          vws->ioctl.num_cap_3d = size / sizeof(uint32_t);
       else
          vws->ioctl.num_cap_3d = SVGA3D_DEVCAP_MAX;
+
+      if (have_drm_2_16) {
+         getenv_val = getenv("SVGA_FORCE_COHERENT");
+         if (getenv_val && strcmp(getenv_val, "0") != 0)
+            vws->force_coherent = TRUE;
+      }
    } else {
       vws->ioctl.num_cap_3d = SVGA3D_DEVCAP_MAX;