[gnome-control-center/wip/hadess/switcheroo-renderers] info: Fix Graphics text with NVidia drivers or >2 GPUs

[Bastien Nocera <hadess src gnome org>]

commit f9c613dc400e298e36623e81469295e4c22dd970
Author: Bastien Nocera <hadess hadess net>
Date:   Mon Oct 28 16:50:49 2019 +0100

    info: Fix Graphics text with NVidia drivers or >2 GPUs
    
    Use switcheroo-control to get the list of GPUs. For each one of the GPUs
    listed, switcheroo-control will give us environment variable we should
    set before running our helper to be able to get the renderer from it.
    
    This means that it will finally work when one of the GPUs is driven
    with the NVidia drivers, as switcheroo-control sets the correct envvars
    for this driver, and that we also support more than 2 GPUs.
    
    Closes: https://gitlab.gnome.org/GNOME/gnome-control-center/merge_requests/601

 panels/info-overview/cc-info-overview-panel.c | 147 ++++++++++++++++++++------
 1 file changed, 113 insertions(+), 34 deletions(-)
---
diff --git a/panels/info-overview/cc-info-overview-panel.c b/panels/info-overview/cc-info-overview-panel.c
index da2c598f9..0d2793658 100644
--- a/panels/info-overview/cc-info-overview-panel.c
+++ b/panels/info-overview/cc-info-overview-panel.c
@@ -231,8 +231,10 @@ get_renderer_from_session (void)
   return renderer;
 }
 
+/* @env is an array of strings with each pair of strings being the
+ * key followed by the value */
 static char *
-get_renderer_from_helper (gboolean discrete_gpu)
+get_renderer_from_helper (const char **env)
 {
   int status;
   char *argv[] = { GNOME_SESSION_DIR "/gnome-session-check-accelerated", NULL };
@@ -240,17 +242,27 @@ get_renderer_from_helper (gboolean discrete_gpu)
   g_autofree char *renderer = NULL;
   g_autoptr(GError) error = NULL;
 
-  if (discrete_gpu)
+  g_debug ("About to launch '%s'", argv[0]);
+
+  if (env != NULL)
     {
+      guint i;
+      g_debug ("With environment:");
       envp = g_get_environ ();
-      envp = g_environ_setenv (envp, "DRI_PRIME", "1", TRUE);
+      for (i = 0; env[i] != NULL; i = i + 2)
+        {
+          g_debug ("  %s = %s", env[i], env[i+1]);
+          envp = g_environ_setenv (envp, env[i], env[i+1], TRUE);
+        }
+    }
+  else
+    {
+      g_debug ("No additional environment variables");
     }
 
   if (!g_spawn_sync (NULL, (char **) argv, envp, 0, NULL, NULL, &renderer, NULL, &status, &error))
     {
-      g_debug ("Failed to get %s GPU: %s",
-               discrete_gpu ? "discrete" : "integrated",
-               error->message);
+      g_debug ("Failed to get GPU: %s", error->message);
       return NULL;
     }
 
@@ -263,13 +275,40 @@ get_renderer_from_helper (gboolean discrete_gpu)
   return info_cleanup (renderer);
 }
 
-static gboolean
-has_dual_gpu (void)
+typedef struct {
+       char *name;
+       gboolean is_default;
+} GpuData;
+
+static int
+gpu_data_sort (gconstpointer a, gconstpointer b)
+{
+  GpuData *gpu_a = (GpuData *) a;
+  GpuData *gpu_b = (GpuData *) b;
+
+  if (gpu_a->is_default)
+    return 1;
+  if (gpu_b->is_default)
+    return -1;
+  return 0;
+}
+
+static void
+gpu_data_free (GpuData *data)
+{
+  g_free (data->name);
+  g_free (data);
+}
+
+static char *
+get_renderer_from_switcheroo (void)
 {
   g_autoptr(GDBusProxy) switcheroo_proxy = NULL;
-  g_autoptr(GVariant) dualgpu_variant = NULL;
-  gboolean ret;
+  g_autoptr(GVariant) variant = NULL;
   g_autoptr(GError) error = NULL;
+  GString *renderers_string;
+  guint i, num_children;
+  GSList *renderers, *l;
 
   switcheroo_proxy = g_dbus_proxy_new_for_bus_sync (G_BUS_TYPE_SYSTEM,
                                                     G_DBUS_PROXY_FLAGS_NONE,
@@ -282,23 +321,71 @@ has_dual_gpu (void)
     {
       g_debug ("Unable to connect to create a proxy for net.hadess.SwitcherooControl: %s",
                error->message);
-      return FALSE;
+      return NULL;
     }
 
-  dualgpu_variant = g_dbus_proxy_get_cached_property (switcheroo_proxy, "HasDualGpu");
+  variant = g_dbus_proxy_get_cached_property (switcheroo_proxy, "GPUs");
 
-  if (!dualgpu_variant)
+  if (!variant)
     {
-      g_debug ("Unable to retrieve net.hadess.SwitcherooControl.HasDualGpu property, the daemon is likely 
not running");
-      return FALSE;
+      g_debug ("Unable to retrieve net.hadess.SwitcherooControl.GPUs property, the daemon is likely not 
running");
+      return NULL;
     }
 
-  ret = g_variant_get_boolean (dualgpu_variant);
+  renderers_string = g_string_new (NULL);
+  num_children = g_variant_n_children (variant);
+  renderers = NULL;
+  for (i = 0; i < num_children; i++)
+    {
+      g_autoptr(GVariant) gpu;
+      g_autoptr(GVariant) name = NULL;
+      g_autoptr(GVariant) env = NULL;
+      g_autoptr(GVariant) is_default = NULL;
+      const char *name_s, **env_s;
+      g_autofree char *renderer = NULL;
+      GpuData *gpu_data;
+
+      gpu = g_variant_get_child_value (variant, i);
+      if (!gpu)
+        continue;
+
+      name = g_variant_lookup_value (gpu, "Name", NULL);
+      env = g_variant_lookup_value (gpu, "Environment", NULL);
+      if (!name || !env)
+        continue;
+      name_s = g_variant_get_string (name, NULL);
+      g_debug ("Getting renderer from helper for GPU '%s'", name_s);
+      env_s = g_variant_get_strv (env, NULL);
+      renderer = get_renderer_from_helper (env_s);
+      g_free (env_s);
+
+      /* We could give up if we don't have a renderer, but that
+       * might just mean gnome-session isn't installed. We fall back
+       * to the device name in udev instead, which is better than nothing */
+
+      gpu_data = g_new0 (GpuData, 1);
+      gpu_data->name = g_strdup (renderer ? renderer : name_s);
+      gpu_data->is_default = is_default ? g_variant_get_boolean (is_default) : FALSE;
+      renderers = g_slist_prepend (renderers, gpu_data);
+    }
 
-  if (ret)
-    g_debug ("Dual-GPU machine detected");
+  renderers = g_slist_sort (renderers, gpu_data_sort);
+  for (l = renderers; l != NULL; l = l->next)
+    {
+      GpuData *data = l->data;
+      if (renderers_string->len > 0)
+        g_string_append (renderers_string, " / ");
+      g_string_append (renderers_string, data->name);
+    }
+  g_slist_free_full (renderers, (GDestroyNotify) gpu_data_free);
+
+  if (renderers_string->len == 0)
+    {
+      g_string_free (renderers_string, TRUE);
+      return NULL;
+    }
 
-  return ret;
+  return g_string_free (renderers_string, FALSE);
 }
 
 static gchar *
@@ -307,22 +394,14 @@ get_graphics_hardware_string (void)
   g_autofree char *discrete_renderer = NULL;
   g_autofree char *renderer = NULL;
 
-  renderer = get_renderer_from_session ();
+  renderer = get_renderer_from_switcheroo ();
   if (!renderer)
-    renderer = get_renderer_from_helper (FALSE);
-  if (has_dual_gpu ())
-    discrete_renderer = get_renderer_from_helper (TRUE);
-
-  if (renderer != NULL)
-    {
-      if (discrete_renderer != NULL)
-        return g_strdup_printf ("%s / %s",
-                                renderer,
-                                discrete_renderer);
-      return g_strdup (renderer);
-    }
-
-  return g_strdup (_("Unknown"));
+    renderer = get_renderer_from_session ();
+  if (!renderer)
+    renderer = get_renderer_from_helper (NULL);
+  if (!renderer)
+    return g_strdup (_("Unknown"));
+  return g_strdup (renderer);
 }
 
 static char *