loader: add function to get render node from dev_t

Add function loader_get_render_node() to help us to get a render node
from dev_t. If the device does not expose a render node, this new
function returns NULL.

As this function uses drmGetDeviceFromDevId(), we bump libdrm minimal
version to 2.4.109.

Signed-off-by: Leandro Ribeiro <leandro.ribeiro@collabora.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11248>

meson.build

@@ -1584,7 +1584,7 @@ _drm_amdgpu_ver = '2.4.107'
 _drm_radeon_ver = '2.4.71'
 _drm_nouveau_ver = '2.4.102'
 _drm_intel_ver = '2.4.75'
-_drm_ver = '2.4.81'
+_drm_ver = '2.4.109'
 
 _libdrm_checks = [
   ['intel', with_dri_i915 or with_gallium_i915],
@@ -1594,17 +1594,6 @@ _libdrm_checks = [
   ['nouveau', (with_gallium_nouveau or with_dri_nouveau)],
 ]
 
-# VC4 only needs core libdrm support of this version, not a libdrm_vc4
-# library.
-if with_gallium_vc4
-  _drm_ver = '2.4.89'
-endif
-
-# etnaviv only needs core libdrm
-if with_gallium_etnaviv
-  _drm_ver = '2.4.89'
-endif
-
 # Loop over the enables versions and get the highest libdrm requirement for all
 # active drivers.
 _drm_blame = ''

src/loader/loader.c

@@ -178,6 +178,26 @@ loader_open_render_node(const char *name)
    return fd;
 }
 
+char *
+loader_get_render_node(dev_t device)
+{
+   char *render_node = NULL;
+   drmDevicePtr dev_ptr;
+
+   if (drmGetDeviceFromDevId(device, 0, &dev_ptr) < 0)
+      return NULL;
+
+   if (dev_ptr->available_nodes & (1 << DRM_NODE_RENDER)) {
+      render_node = strdup(dev_ptr->nodes[DRM_NODE_RENDER]);
+      if (!render_node)
+         log_(_LOADER_DEBUG, "MESA-LOADER: failed to allocate memory for render node\n");
+   }
+
+   drmFreeDevice(&dev_ptr);
+
+   return render_node;
+}
+
 #ifdef USE_DRICONF
 static const driOptionDescription __driConfigOptionsLoader[] = {
     DRI_CONF_SECTION_INITIALIZATION
@@ -376,6 +396,12 @@ loader_open_render_node(const char *name)
    return -1;
 }
 
+char *
+loader_get_render_node(dev_t device)
+{
+   return NULL;
+}
+
 int loader_get_user_preferred_fd(int default_fd, bool *different_device)
 {
    *different_device = false;

src/loader/loader.h

@@ -28,6 +28,7 @@
 #define LOADER_H
 
 #include <stdbool.h>
+#include <sys/stat.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -43,6 +44,9 @@ loader_open_device(const char *);
 int
 loader_open_render_node(const char *name);
 
+char *
+loader_get_render_node(dev_t device);
+
 bool
 loader_get_pci_id_for_fd(int fd, int *vendor_id, int *chip_id);