v2: Fix the leak of device_name
v3: Rebased
It enables to use the DRI_PRIME env var to specify
which gpu to use.
Two syntax are supported:
If DRI_PRIME is 1 it means: take any other gpu than the default one.
If DRI_PRIME is the ID_PATH_TAG of a device: choose this device if
possible.
The ID_PATH_TAG is a tag filled by udev.
You can check it with 'udevadm info' on the device node.
For example it can be "pci-0000_01_00_0".
Render-nodes need to be enabled to choose another gpu,
and they need to have the ID_PATH_TAG advertised.
It is possible for not very recent udev that the tag
is not advertised for render-nodes, then
ones need to add a file containing:
SUBSYSTEM=="drm", IMPORT{builtin}="path_id"
in /etc/udev/rules.d/
Signed-off-by: Axel Davy <axel.d...@ens.fr>
---
src/loader/loader.c | 185 ++++++++++++++++++++++++++++++++++++++++++++++++++++
src/loader/loader.h | 7 ++
2 files changed, 192 insertions(+)
diff --git a/src/loader/loader.c b/src/loader/loader.c
index 0f26265..19d99d5 100644
--- a/src/loader/loader.c
+++ b/src/loader/loader.c
@@ -70,6 +70,10 @@
#ifdef HAVE_LIBUDEV
#include <assert.h>
#include <dlfcn.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
#endif
#ifdef HAVE_SYSFS
#include <sys/stat.h>
@@ -214,6 +218,187 @@ out:
return (*chip_id >= 0);
}
+
+static char *
+get_render_node_from_id_path_tag(struct udev *udev,
+ char *id_path_tag,
+ char another_tag)
+{
+ struct udev_device *device;
+ struct udev_enumerate *e;
+ struct udev_list_entry *entry;
+ const char *path, *id_path_tag_tmp;
+ char *path_res;
+ char found = 0;
+ UDEV_SYMBOL(struct udev_enumerate *, udev_enumerate_new,
+ (struct udev *));
+ UDEV_SYMBOL(int, udev_enumerate_add_match_subsystem,
+ (struct udev_enumerate *, const char *));
+ UDEV_SYMBOL(int, udev_enumerate_add_match_sysname,
+ (struct udev_enumerate *, const char *));
+ UDEV_SYMBOL(int, udev_enumerate_scan_devices,
+ (struct udev_enumerate *));
+ UDEV_SYMBOL(struct udev_list_entry *, udev_enumerate_get_list_entry,
+ (struct udev_enumerate *));
+ UDEV_SYMBOL(struct udev_list_entry *, udev_list_entry_get_next,
+ (struct udev_list_entry *));
+ UDEV_SYMBOL(const char *, udev_list_entry_get_name,
+ (struct udev_list_entry *));
+ UDEV_SYMBOL(struct udev_device *, udev_device_new_from_syspath,
+ (struct udev *, const char *));
+ UDEV_SYMBOL(const char *, udev_device_get_property_value,
+ (struct udev_device *, const char *));
+ UDEV_SYMBOL(const char *, udev_device_get_devnode,
+ (struct udev_device *));
+ UDEV_SYMBOL(struct udev_device *, udev_device_unref,
+ (struct udev_device *));
+
+ e = udev_enumerate_new(udev);
+ udev_enumerate_add_match_subsystem(e, "drm");
+ udev_enumerate_add_match_sysname(e, "render*");
+
+ udev_enumerate_scan_devices(e);
+ udev_list_entry_foreach(entry, udev_enumerate_get_list_entry(e)) {
+ path = udev_list_entry_get_name(entry);
+ device = udev_device_new_from_syspath(udev, path);
+ if (!device)
+ continue;
+ id_path_tag_tmp = udev_device_get_property_value(device, "ID_PATH_TAG");
+ if (id_path_tag_tmp) {
+ if ((!another_tag && !strcmp(id_path_tag, id_path_tag_tmp)) ||
+ (another_tag && strcmp(id_path_tag, id_path_tag_tmp))) {
+ found = 1;
+ break;
+ }
+ }
+ udev_device_unref(device);
+ }
+
+ if (found) {
+ path_res = strdup(udev_device_get_devnode(device));
+ udev_device_unref(device);
+ return path_res;
+ }
+ return NULL;
+}
+
+static char *
+get_id_path_tag_from_fd(struct udev *udev, int fd)
+{
+ struct udev_device *device;
+ const char *id_path_tag_tmp;
+ char *id_path_tag;
+ UDEV_SYMBOL(const char *, udev_device_get_property_value,
+ (struct udev_device *, const char *));
+ UDEV_SYMBOL(struct udev_device *, udev_device_unref,
+ (struct udev_device *));
+
+ device = udev_device_new_from_fd(udev, fd);
+ if (!device)
+ return NULL;
+
+ id_path_tag_tmp = udev_device_get_property_value(device, "ID_PATH_TAG");
+ if (!id_path_tag_tmp)
+ return NULL;
+
+ id_path_tag = strdup(id_path_tag_tmp);
+
+ udev_device_unref(device);
+ return id_path_tag;
+}
+
+static int
+drm_open_device(const char *device_name)
+{
+ int fd;
+#ifdef O_CLOEXEC
+ fd = open(device_name, O_RDWR | O_CLOEXEC);
+ if (fd == -1 && errno == EINVAL)
+#endif
+ {
+ fd = open(device_name, O_RDWR);
+ if (fd != -1)
+ fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
+ }
+ return fd;
+}
+
+int loader_get_user_preferred_fd(int default_fd, int *different_device)
+{
+ struct udev *udev;
+ const char *dri_prime = getenv("DRI_PRIME");
+ char *prime = NULL;
+ int is_different_device = 0, fd = default_fd;
+ char *default_device_id_path_tag;
+ char *device_name = NULL;
+ char another_tag = 0;
+ UDEV_SYMBOL(struct udev *, udev_new, (void));
+ UDEV_SYMBOL(struct udev *, udev_unref, (struct udev *));
+
+ if (dri_prime)
+ prime = strdup(dri_prime);
+
+ if (prime == NULL) {
+ *different_device = 0;
+ return default_fd;
+ }
+
+ udev = udev_new();
+ if (!udev)
+ goto prime_clean;
+
+ default_device_id_path_tag = get_id_path_tag_from_fd(udev, default_fd);
+ if (!default_device_id_path_tag)
+ goto udev_clean;
+
+ is_different_device = 1;
+ /* two format are supported:
+ * "1": choose any other card than the card used by default.
+ * id_path_tag: (for example "pci-0000_02_00_0") choose the card
+ * with this id_path_tag.
+ */
+ if (!strcmp(prime,"1")) {
+ free(prime);
+ prime = strdup(default_device_id_path_tag);
+ /* request a card with a different card than the default card */
+ another_tag = 1;
+ } else if (!strcmp(default_device_id_path_tag, prime))
+ /* we are to get a new fd (render-node) of the same device */
+ is_different_device = 0;
+
+ device_name = get_render_node_from_id_path_tag(udev,
+ prime,
+ another_tag);
+ if (device_name == NULL) {
+ is_different_device = 0;
+ goto default_device_clean;
+ }
+
+ fd = drm_open_device(device_name);
+ if (fd > 0) {
+ close(default_fd);
+ } else {
+ fd = default_fd;
+ is_different_device = 0;
+ }
+ free(device_name);
+
+ default_device_clean:
+ free(default_device_id_path_tag);
+ udev_clean:
+ udev_unref(udev);
+ prime_clean:
+ free(prime);
+
+ *different_device = is_different_device;
+ return fd;
+}
+#else
+int loader_get_user_preferred_fd(int default_fd, int *different_device)
+{
+ *different_device = 0;
+ return default_fd;
+}
#endif
#if defined(HAVE_SYSFS)
diff --git a/src/loader/loader.h b/src/loader/loader.h
index dfd77ba..fa57950 100644
--- a/src/loader/loader.h
+++ b/src/loader/loader.h
@@ -41,6 +41,13 @@ loader_get_driver_for_fd(int fd, unsigned driver_types);
char *
loader_get_device_name_for_fd(int fd);
+/* Function to get a different device than the one we are to use by default,
+ * if the user requests so and it is possible. The initial fd will be closed
+ * if neccessary. The returned fd is potentially a render-node.
+ */
+
+int
+loader_get_user_preferred_fd(int default_fd, int *different_device);
/* for logging.. keep this aligned with egllog.h so we can just use
* _eglLog directly.
--
1.9.1
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