egldevice: implement EGL_MESA_device_hashdevice-hash

Use the hash table string hashing function as it's probably fine. The
hash is taken of the string of the vendor and device IDs from the PCI
bus.

Signed-off-by: Jonny Lamb <jonny.lamb@collabora.co.uk>

3 files changed, 71 insertions, 1 deletions

diff --git a/src/egl/main/Makefile.am b/src/egl/main/Makefile.am
index 9030d272b5..e2811371de 100644
--- a/src/egl/main/Makefile.am
+++ b/src/egl/main/Makefile.am
@@ -23,6 +23,7 @@ include Makefile.sources
 
 AM_CFLAGS = \
 	-I$(top_srcdir)/include \
+	-I$(top_srcdir)/src \
 	-I$(top_srcdir)/src/gbm/main \
 	$(DEFINES) \
 	$(VISIBILITY_CFLAGS) \
@@ -37,6 +38,7 @@ libEGL_la_SOURCES = \
 	${LIBEGL_C_FILES}
 
 libEGL_la_LIBADD = \
+	$(top_builddir)/src/util/libmesautil.la
 	$(EGL_LIB_DEPS)
 libEGL_la_LDFLAGS = \
 	-no-undefined \
diff --git a/src/egl/main/egldevice.c b/src/egl/main/egldevice.c
index 8a717a6c6a..69121e6812 100644
--- a/src/egl/main/egldevice.c
+++ b/src/egl/main/egldevice.c
@@ -34,6 +34,8 @@
 #include <assert.h>
 #include <string.h>
 
+#include "util/hash_table.h"
+
 #include "eglcurrent.h"
 #include "egldevice.h"
 #include "egldriver.h"
@@ -79,7 +81,7 @@ _eglEnsureDeviceInfo(EGLBoolean get_devices)
 
       /* update this string like in eglglobals.c to add support for a device
        * extension */
-      info->extensions = "";
+      info->extensions = "EGL_MESA_device_hash";
 
 #ifdef HAVE_LIBUDEV
       info->udev = NULL;
@@ -216,6 +218,64 @@ _eglFiniDeviceInfo(void)
    _eglGlobal.DeviceInfo = NULL;
 }
 
+static EGLBoolean
+_eglQueryDeviceHash(_EGLDevice *device,
+                    EGLAttrib *value)
+{
+#ifdef HAVE_LIBUDEV
+   struct udev_device *parent;
+   EGLBoolean ret = EGL_TRUE;
+   const char *subsystem_vendor, *subsystem_device;
+   char *str;
+   int len;
+   UDEV_SYMBOL(struct udev_device *, udev_device_get_parent_with_subsystem_devtype,
+               (struct udev_device *, const char *, const char *));
+   UDEV_SYMBOL(const char *, udev_device_get_sysattr_value,
+               (struct udev_device *, const char *));
+
+   if (dlsym_failed)
+      return EGL_FALSE;
+
+   assert(device->Hash == 0);
+
+   mtx_lock(_eglGlobal.Mutex);
+
+   parent = udev_device_get_parent_with_subsystem_devtype(
+      device->Info, "pci", NULL);
+
+   if (!parent) {
+      ret = EGL_FALSE;
+      goto out;
+   }
+
+   subsystem_vendor = udev_device_get_sysattr_value(parent, "subsystem_vendor");
+   subsystem_device = udev_device_get_sysattr_value(parent, "subsystem_device");
+
+   if (!subsystem_vendor || !subsystem_device) {
+      ret = EGL_FALSE;
+      goto out;
+   }
+
+   len = strlen(subsystem_vendor) + strlen(subsystem_device);
+   str = calloc(len + 1, sizeof(char));
+
+   str = strdup(subsystem_vendor);
+   strcat(str, subsystem_device);
+
+   *value = _mesa_hash_string(str);
+
+   device->Hash = *value;
+
+   free(str);
+
+out:
+   mtx_unlock(_eglGlobal.Mutex);
+   return ret;
+#else
+   return EGL_FALSE;
+#endif
+}
+
 /**
  * Get attribute about specific device
  */
@@ -228,6 +288,13 @@ _eglQueryDeviceAttribEXT(_EGLDevice *device,
       return _eglError(EGL_BAD_PARAMETER, "eglQueryDeviceAttribEXT");
 
    switch (attribute) {
+   case EGL_DEVICE_HASH_MESA:
+      if (device->Hash > 0) {
+         return device->Hash;
+      } else {
+         return _eglQueryDeviceHash(device, value);
+      }
+      break;
    default:
       return _eglError(EGL_BAD_ATTRIBUTE, "eglQueryDeviceAttribEXT");
       break;
diff --git a/src/egl/main/egldevice.h b/src/egl/main/egldevice.h
index 2c7986acb7..fb30bd2050 100644
--- a/src/egl/main/egldevice.h
+++ b/src/egl/main/egldevice.h
@@ -37,6 +37,7 @@ struct _egl_device {
    _EGLDevice *Next;
 
    void *Info;
+   EGLint Hash;
 };