loader: add driver list as parameter in loader_open_render_node_platform_device()

In a later commit in this series, we'll need to open the first supported
render-only platform device that we can find.

In order to avoid calling loader_open_render_node_platform_device()
multiple times (what is quite expensive), change this function to take a
driver list (instead of a single driver name) as parameter.

Signed-off-by: Leandro Ribeiro <leandro.ribeiro@collabora.com>
Reviewed-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24825>

src/gallium/drivers/tegra/tegra_screen.c

@@ -572,6 +572,7 @@ struct pipe_screen *
 tegra_screen_create(int fd)
 {
    struct tegra_screen *screen;
+   const char * const drivers[] = {"nouveau"};
 
    screen = calloc(1, sizeof(*screen));
    if (!screen)
@@ -579,7 +580,8 @@ tegra_screen_create(int fd)
 
    screen->fd = fd;
 
-   screen->gpu_fd = loader_open_render_node_platform_device("nouveau");
+   screen->gpu_fd =
+      loader_open_render_node_platform_device(drivers, ARRAY_SIZE(drivers));
    if (screen->gpu_fd < 0) {
       if (errno != ENOENT)
          fprintf(stderr, "failed to open GPU device: %s\n", strerror(errno));

src/loader/loader.c

@@ -132,11 +132,19 @@ iris_predicate(int fd)
    return ret;
 }
 
+/**
+ * Goes through all the platform devices whose driver is on the given list and
+ * try to open their render node. It returns the fd of the first device that
+ * it can open.
+ */
 int
-loader_open_render_node_platform_device(const char *name)
+loader_open_render_node_platform_device(const char * const drivers[],
+                                        unsigned int n_drivers)
 {
    drmDevicePtr devices[MAX_DRM_DEVICES], device;
-   int i, num_devices, fd = -1;
+   int num_devices, fd = -1;
+   int i, j;
+   bool found = false;
 
    num_devices = drmGetDevices2(0, devices, MAX_DRM_DEVICES);
    if (num_devices <= 0)
@@ -159,7 +167,13 @@ loader_open_render_node_platform_device(const char *name)
             continue;
          }
 
-         if (strcmp(version->name, name) != 0) {
+         for (j = 0; j < n_drivers; j++) {
+            if (strcmp(version->name, drivers[j]) == 0) {
+               found = true;
+               break;
+            }
+         }
+         if (!found) {
             drmFreeVersion(version);
             close(fd);
             continue;

src/loader/loader.h

@@ -44,7 +44,8 @@ int
 loader_open_device(const char *);
 
 int
-loader_open_render_node_platform_device(const char *name);
+loader_open_render_node_platform_device(const char * const drivers[],
+                                        unsigned int n_drivers);
 
 char *
 loader_get_render_node(dev_t device);