[Mesa-dev] [RFC] egl/android: Add DRM node probing and filtering

[Robert Foss]

This patch both adds support for probing & filtering DRM nodes
and switches away from using the GRALLOC_MODULE_PERFORM_GET_DRM_FD
gralloc call.

Currently the filtering is based just on the driver name,
and the desired name is supplied using the "drm.gpu.vendor_name"
Android property.

The filtering itself is done using the newly introduced
libdrm drmHandleMatch() call.

Signed-off-by: Robert Foss <robert.foss at collabora.com>
---

This patch is based on[1], which contains a new libdrm function,
called drmHandleMatch(), which allows for matching an opened
drm node handle against some desired properties.

A choice that was made for this patch was to add support for
falling back to to DRM nodes that have failed the filtering,
if no node passes the filter.
If this wouldn't be useful to anyone, I would suggest ripping it
out since it is a little bit ugly&complex.


[1] https://www.spinics.net/lists/dri-devel/msg172497.html


 src/egl/drivers/dri2/platform_android.c | 72 ++++++++++++++++++++++++++++-----
 1 file changed, 62 insertions(+), 10 deletions(-)

diff --git a/src/egl/drivers/dri2/platform_android.c b/src/egl/drivers/dri2/platform_android.c
index 7f1a496ea24..0b082fe5dcc 100644
--- a/src/egl/drivers/dri2/platform_android.c
+++ b/src/egl/drivers/dri2/platform_android.c
@@ -27,6 +27,7 @@
  * DEALINGS IN THE SOFTWARE.
  */
 
+#include <cutils/properties.h>
 #include <errno.h>
 #include <dlfcn.h>
 #include <fcntl.h>
@@ -1117,18 +1118,69 @@ droid_add_configs_for_visuals(_EGLDriver *drv, _EGLDisplay *dpy)
 static int
 droid_open_device(struct dri2_egl_display *dri2_dpy)
 {
-   int fd = -1, err = -EINVAL;
-
-   if (dri2_dpy->gralloc->perform)
-         err = dri2_dpy->gralloc->perform(dri2_dpy->gralloc,
-                                          GRALLOC_MODULE_PERFORM_GET_DRM_FD,
-                                          &fd);
-   if (err || fd < 0) {
-      _eglLog(_EGL_WARNING, "fail to get drm fd");
-      fd = -1;
+   int prop_set, num_devices, ret;
+   const int node_type = DRM_NODE_RENDER;
+   int fd = -1, fallback_fd = -1;
+
+   const int MAX_DRM_DEVICES = 32;
+   char vendor_name[PROPERTY_VALUE_MAX];
+   prop_set = property_get("drm.gpu.vendor_name", vendor_name, NULL);
+   drmVersion ver_filter;
+   ver_filter.name = vendor_name;
+
+   drmDevicePtr devices[MAX_DRM_DEVICES];
+   num_devices = drmGetDevices2(0, devices, MAX_DRM_DEVICES);
+   if (num_devices < 0) {
+      _eglLog(_EGL_WARNING, "Failed to find any DRM devices");
+      return -1;
+   }
+
+   for (int i = 0; i < num_devices; i++) {
+      /* Filter out DRM_NODE_ types we aren't interested in */
+      if (!(devices[i]->available_nodes & (1 << node_type))) {
+         continue;
+      }
+
+      /* Open DRM node FD */
+      fd = loader_open_device(devices[i]->nodes[node_type]);
+      if (fd == -1 && errno == EINVAL) {
+         _eglLog(_EGL_WARNING, "%s()  node #%d failed to open", __func__, i);
+         continue;
+      }
+
+      /* See if FD matches the driver vendor we want */
+      if (prop_set && !drmHandleMatch(fd, &ver_filter, NULL)){
+         _eglLog(_EGL_WARNING, "%s()  node #%d  FD=%d does not match filter", __func__, i , fd);
+         goto next;
+      }
+
+      /* Successfully found matching FD */
+      close(fallback_fd);
+      fallback_fd = -1;
+      break;
+
+next:
+      if (fallback_fd == -1) {
+         fallback_fd = fd;
+         fd = -1;
+      } else {
+         close(fd);
+         fd = -1;
+      }
+      continue;
+   }
+
+   if (fallback_fd < 0 && fd < 0) {
+      _eglLog(_EGL_WARNING, "Failed to open any DRM handle");
+      return -1;
+   }
+
+   if (fd < 0) {
+      _eglLog(_EGL_WARNING, "Failed to open desired DRM handle, using fallback");
+      return fallback_fd;
    }
 
-   return (fd >= 0) ? fcntl(fd, F_DUPFD_CLOEXEC, 3) : -1;
+   return fd;
 }
 
 static const struct dri2_egl_display_vtbl droid_display_vtbl = {
-- 
2.14.1