[cogl/halfline/wip/render-node: 6/6] kms-winsys: support drm render nodes

[Ray Strode <halfline src gnome org>]

commit e378936c88d38bac20959c185f2a88b9f6ec908a
Author: Ray Strode <rstrode redhat com>
Date:   Wed Aug 26 17:02:45 2015 -0400

    kms-winsys: support drm render nodes
    
    Right now cogl does all rendering and modesetting using
    /dev/dri/card0. If rendering were moved to /dev/dri/renderD128
    then it will be in a better position to support offloading
    rendering operations to a secondary gpu.
    
    Also, some drivers (some versions of the vmware driver) don't
    support using card0 when VT switched away.  The result is crashes.
    
    This commit leaves card0 for modesetting operations, but defers
    rendering operations to the the render node.  The output is synchronized
    to card0 using dma-buf.

 cogl/winsys/cogl-winsys-egl-kms.c |   91 ++++++++++++++++++++++++++++++++-----
 1 files changed, 79 insertions(+), 12 deletions(-)
---
diff --git a/cogl/winsys/cogl-winsys-egl-kms.c b/cogl/winsys/cogl-winsys-egl-kms.c
index fd0f6f4..ae7c400 100644
--- a/cogl/winsys/cogl-winsys-egl-kms.c
+++ b/cogl/winsys/cogl-winsys-egl-kms.c
@@ -46,6 +46,7 @@
 #include <xf86drmMode.h>
 #include <gbm.h>
 #include <glib.h>
+#include <glob.h>
 #include <sys/fcntl.h>
 #include <unistd.h>
 #include <string.h>
@@ -76,6 +77,8 @@ typedef struct _CoglRendererDeviceKMS
 typedef struct _CoglRendererKMS
 {
   CoglRendererDeviceKMS card_device;
+  CoglRendererDeviceKMS rendering_device;
+  struct gbm_device     *gbm_for_egl;
   CoglClosure *swap_notify_idle;
   CoglBool     page_flips_not_supported;
 } CoglRendererKMS;
@@ -115,6 +118,7 @@ typedef struct _CoglOnscreenKMS
   uint32_t next_fb_id;
   struct gbm_bo *current_bo;
   struct gbm_bo *next_bo;
+  struct gbm_bo *card_bo;
   CoglBool pending_swap_notify;
 
   EGLSurface *pending_egl_surface;
@@ -122,6 +126,7 @@ typedef struct _CoglOnscreenKMS
 } CoglOnscreenKMS;
 
 static const char card_device_name[] = "/dev/dri/card0";
+static const char rendering_device_glob[] = "/dev/dri/renderD*";
 
 static void
 _cogl_winsys_renderer_disconnect (CoglRenderer *renderer)
@@ -135,9 +140,15 @@ _cogl_winsys_renderer_disconnect (CoglRenderer *renderer)
   if (kms_renderer->card_device.gbm != NULL)
     gbm_device_destroy (kms_renderer->card_device.gbm);
 
+  if (kms_renderer->rendering_device.gbm != NULL)
+    gbm_device_destroy (kms_renderer->rendering_device.gbm);
+
   if (kms_renderer->card_device.is_borrowed && kms_renderer->card_device.fd >= 0)
     close (kms_renderer->card_device.fd);
 
+  if (kms_renderer->rendering_device.is_borrowed && kms_renderer->rendering_device.fd >= 0)
+    close (kms_renderer->rendering_device.fd);
+
   g_slice_free (CoglRendererKMS, kms_renderer);
   g_slice_free (CoglRendererEGL, egl_renderer);
 }
@@ -255,6 +266,9 @@ process_flip (CoglFlipKMS *flip)
       kms_onscreen->current_bo = kms_onscreen->next_bo;
       kms_onscreen->next_bo = NULL;
 
+      gbm_bo_destroy (kms_onscreen->card_bo);
+      kms_onscreen->card_bo = NULL;
+
       cogl_object_unref (flip->onscreen);
 
       g_slice_free (CoglFlipKMS, flip);
@@ -306,6 +320,8 @@ _cogl_winsys_renderer_connect (CoglRenderer *renderer,
 {
   CoglRendererEGL *egl_renderer;
   CoglRendererKMS *kms_renderer;
+  glob_t glob_buffer = { 0 };
+  int ret;
 
   renderer->winsys = g_slice_new0 (CoglRendererEGL);
   egl_renderer = renderer->winsys;
@@ -314,10 +330,34 @@ _cogl_winsys_renderer_connect (CoglRenderer *renderer,
   egl_renderer->platform = g_slice_new0 (CoglRendererKMS);
   kms_renderer = egl_renderer->platform;
 
-  kms_renderer->card_device.fd = -1;
-
   egl_renderer->edpy = EGL_NO_DISPLAY;
 
+  kms_renderer->rendering_device.fd = -1;
+
+  ret = glob (rendering_device_glob, 0, NULL, &glob_buffer);
+
+  if (ret != GLOB_NOMATCH)
+    {
+      kms_renderer->rendering_device.fd = open (glob_buffer.gl_pathv[0], O_RDWR);
+
+      if (kms_renderer->rendering_device.fd < 0)
+        g_debug ("could not open '%s': %m", glob_buffer.gl_pathv[0]);
+    }
+
+  globfree (&glob_buffer);
+
+  if (kms_renderer->rendering_device.fd >= 0)
+    {
+      kms_renderer->rendering_device.gbm = gbm_create_device (kms_renderer->rendering_device.fd);
+      if (kms_renderer->rendering_device.gbm != NULL)
+        {
+          egl_renderer->edpy = eglGetDisplay ((EGLNativeDisplayType)kms_renderer->rendering_device.gbm);
+          kms_renderer->gbm_for_egl = kms_renderer->rendering_device.gbm;
+        }
+    }
+
+  kms_renderer->card_device.fd = -1;
+
   if (renderer->kms_fd >= 0)
     {
       kms_renderer->card_device.fd = renderer->kms_fd;
@@ -345,13 +385,18 @@ _cogl_winsys_renderer_connect (CoglRenderer *renderer,
       goto fail;
     }
 
-  egl_renderer->edpy = eglGetDisplay ((EGLNativeDisplayType)kms_renderer->card_device.gbm);
   if (egl_renderer->edpy == EGL_NO_DISPLAY)
     {
-      _cogl_set_error (error, COGL_WINSYS_ERROR,
-                   COGL_WINSYS_ERROR_INIT,
-                   "Couldn't get eglDisplay");
-      goto fail;
+      egl_renderer->edpy = eglGetDisplay ((EGLNativeDisplayType)kms_renderer->card_device.gbm);
+      if (egl_renderer->edpy == EGL_NO_DISPLAY)
+        {
+          _cogl_set_error (error, COGL_WINSYS_ERROR,
+                       COGL_WINSYS_ERROR_INIT,
+                       "Couldn't get eglDisplay");
+          goto fail;
+        }
+
+      kms_renderer->gbm_for_egl = kms_renderer->card_device.gbm;
     }
 
   if (!_cogl_winsys_egl_renderer_connect_common (renderer, error))
@@ -808,7 +853,7 @@ _cogl_winsys_egl_context_created (CoglDisplay *display,
        COGL_EGL_WINSYS_FEATURE_SURFACELESS_CONTEXT) == 0)
     {
       kms_display->dummy_gbm_surface =
-        gbm_surface_create (kms_renderer->card_device.gbm,
+        gbm_surface_create (kms_renderer->gbm_for_egl,
                             16, 16,
                             GBM_FORMAT_XRGB8888,
                             GBM_BO_USE_RENDERING);
@@ -883,7 +928,7 @@ _cogl_winsys_onscreen_swap_buffers_with_damage (CoglOnscreen *onscreen,
   CoglRendererKMS *kms_renderer = egl_renderer->platform;
   CoglOnscreenEGL *egl_onscreen = onscreen->winsys;
   CoglOnscreenKMS *kms_onscreen = egl_onscreen->platform;
-  uint32_t handle, stride;
+  uint32_t handle = 0, stride;
   CoglFlipKMS *flip;
 
   /* If we already have a pending swap then block until it completes */
@@ -914,7 +959,27 @@ _cogl_winsys_onscreen_swap_buffers_with_damage (CoglOnscreen *onscreen,
   /* Now we need to set the CRTC to whatever is the front buffer */
   kms_onscreen->next_bo = gbm_surface_lock_front_buffer (kms_onscreen->surface);
   stride = gbm_bo_get_stride (kms_onscreen->next_bo);
-  handle = gbm_bo_get_handle (kms_onscreen->next_bo).u32;
+
+  if (kms_renderer->rendering_device.gbm != NULL)
+    {
+      struct gbm_import_fd_data dma_buf_data = { 0 };
+
+      dma_buf_data.fd = gbm_bo_get_fd (kms_onscreen->next_bo);
+      dma_buf_data.width = gbm_bo_get_width (kms_onscreen->next_bo);
+      dma_buf_data.height = gbm_bo_get_height (kms_onscreen->next_bo);
+      dma_buf_data.stride = gbm_bo_get_stride (kms_onscreen->next_bo);
+      dma_buf_data.format = gbm_bo_get_format (kms_onscreen->next_bo);
+
+      kms_onscreen->card_bo = gbm_bo_import (kms_renderer->card_device.gbm,
+                                             GBM_BO_IMPORT_FD,
+                                             &dma_buf_data,
+                                             GBM_BO_USE_SCANOUT);
+      if (kms_onscreen->card_bo != NULL)
+        handle = gbm_bo_get_handle (kms_onscreen->card_bo).u32;
+    }
+
+  if (handle == 0)
+    handle = gbm_bo_get_handle (kms_onscreen->next_bo).u32;
 
   if (drmModeAddFB (kms_renderer->card_device.fd,
                     kms_display->width,
@@ -926,6 +991,7 @@ _cogl_winsys_onscreen_swap_buffers_with_damage (CoglOnscreen *onscreen,
                     &kms_onscreen->next_fb_id))
     {
       g_warning ("Failed to create new back buffer handle: %m");
+      g_clear_pointer (&kms_onscreen->card_bo, gbm_bo_destroy);
       gbm_surface_release_buffer (kms_onscreen->surface,
                                   kms_onscreen->next_bo);
       kms_onscreen->next_bo = NULL;
@@ -949,6 +1015,7 @@ _cogl_winsys_onscreen_swap_buffers_with_damage (CoglOnscreen *onscreen,
   if (flip->pending == 0)
     {
       drmModeRmFB (kms_renderer->card_device.fd, kms_onscreen->next_fb_id);
+      g_clear_pointer (&kms_onscreen->card_bo, gbm_bo_destroy);
       gbm_surface_release_buffer (kms_onscreen->surface,
                                   kms_onscreen->next_bo);
       kms_onscreen->next_bo = NULL;
@@ -1023,7 +1090,7 @@ _cogl_winsys_onscreen_init (CoglOnscreen *onscreen,
   egl_onscreen->platform = kms_onscreen;
 
   kms_onscreen->surface =
-    gbm_surface_create (kms_renderer->card_device.gbm,
+    gbm_surface_create (kms_renderer->gbm_for_egl,
                         kms_display->width,
                         kms_display->height,
                         GBM_FORMAT_XRGB8888,
@@ -1224,7 +1291,7 @@ cogl_kms_display_set_layout (CoglDisplay *display,
 
       /* Need to drop the GBM surface and create a new one */
 
-      new_surface = gbm_surface_create (kms_renderer->card_device.gbm,
+      new_surface = gbm_surface_create (kms_renderer->gbm_for_egl,
                                         width, height,
                                         GBM_FORMAT_XRGB8888,
                                         GBM_BO_USE_SCANOUT |