libkms: Pick driver backend via pci id that we get from udev

libkms/Makefile.am

@@ -5,9 +5,11 @@ AM_CFLAGS = \
 libkms_la_LTLIBRARIES = libkms.la
 libkms_ladir = $(libdir)
 libkms_la_LDFLAGS = -version-number 1:0:0 -no-undefined
-libkms_la_LIBADD =
+libkms_la_LIBADD = \
+	$(LIBUDEV_LIBS)
 
 libkms_la_SOURCES = \
+	linux.c \
 	api.c
 
 if HAVE_VMWGFX

libkms/api.c

@@ -32,13 +32,34 @@
 #include <string.h>
 #include "internal.h"
 
+struct create_record
+{
+	unsigned vendor;
+	unsigned chip;
+	int (*func)(int fd, struct kms_driver **out);
+};
+
+static struct create_record table[] = {
+#ifdef HAVE_VMWGFX
+	{ 0x15ad, 0x0405, vmwgfx_create }, /* VMware vGPU */
+#endif
+	{ 0, 0, NULL },
+};
+
 int kms_create(int fd, struct kms_driver **out)
 {
-#ifdef HAVE_VMWGFX
-	return vmwgfx_create(fd, out);
-#else
+	unsigned vendor_id, chip_id;
+	int ret, i;
+
+	ret = linux_get_pciid_from_fd(fd, &vendor_id, &chip_id);
+	if (ret)
+		return ret;
+
+	for (i = 0; table[i].func; i++)
+		if (table[i].vendor == vendor_id && table[i].chip == chip_id)
+			return table[i].func(fd, out);
+
 	return -ENOSYS;
-#endif
 }
 
 int kms_get_prop(struct kms_driver *kms, unsigned key, unsigned *out)

libkms/internal.h

@@ -62,6 +62,8 @@ struct kms_bo
 	unsigned handle;
 };
 
+int linux_get_pciid_from_fd(int fd, unsigned *vendor_id, unsigned *chip_id);
+
 int vmwgfx_create(int fd, struct kms_driver **out);
 
 #endif

libkms/linux.c

@@ -0,0 +1,88 @@
+/**************************************************************************
+ *
+ * Copyright © 2009 VMware, Inc., Palo Alto, CA., USA
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+/*
+ * Thanks to krh and jcristau for the tips on
+ * going from fd to pci id via fstat and udev.
+ */
+
+
+#include <errno.h>
+#include <stdio.h>
+#include <xf86drm.h>
+#include <sys/stat.h>
+
+#include "internal.h"
+
+#define LIBUDEV_I_KNOW_THE_API_IS_SUBJECT_TO_CHANGE
+#include <libudev.h>
+
+int linux_get_pciid_from_fd(int fd, unsigned *vendor_id, unsigned *chip_id)
+{
+	struct udev *udev;
+	struct udev_device *device;
+	struct udev_device *parent;
+	const char *pci_id;
+	struct stat buffer;
+	int ret;
+
+	ret = fstat(fd, &buffer);
+	if (ret)
+		return -EINVAL;
+
+	if (!S_ISCHR(buffer.st_mode))
+		return -EINVAL;
+
+	udev = udev_new();
+	if (!udev)
+		return -ENOMEM;
+
+	device = udev_device_new_from_devnum(udev, 'c', buffer.st_rdev);
+	if (!device)
+		goto err_free_udev;
+
+	parent = udev_device_get_parent(device);
+	if (!parent)
+		goto err_free_device;
+
+	pci_id = udev_device_get_property_value(parent, "PCI_ID");
+	if (!pci_id)
+		goto err_free_device;
+
+	if (sscanf(pci_id, "%x:%x", vendor_id, chip_id) != 2)
+		goto err_free_device;
+
+	udev_device_unref(device);
+	udev_unref(udev);
+
+	return 0;
+
+err_free_device:
+	udev_device_unref(device);
+err_free_udev:
+	udev_unref(udev);
+	return -EINVAL;
+}