IABSD.fr/xenocara/lib/libdrm/libkms/linux.c

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• Author : jsg
  Date : 2018-09-13 12:02:27
  Hash : d4accf84
  Message : Merge libdrm 2.4.94

• lib/libdrm/libkms/linux.c

• /**************************************************************************
   *
   * 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 <stdlib.h>
  #include <xf86drm.h>
  #include <string.h>
  #include <unistd.h>
  #include <sys/stat.h>
  #include <sys/types.h>
  #ifdef MAJOR_IN_MKDEV
  #include <sys/mkdev.h>
  #endif
  #ifdef MAJOR_IN_SYSMACROS
  #include <sys/sysmacros.h>
  #endif
  
  #include "libdrm_macros.h"
  #include "internal.h"
  
  #define PATH_SIZE 512
  
  static int
  linux_name_from_sysfs(int fd, char **out)
  {
  	char path[PATH_SIZE+1] = ""; /* initialize to please valgrind */
  	char link[PATH_SIZE+1] = "";
  	struct stat buffer;
  	unsigned maj, min;
  	char* slash_name;
  	int ret;
  
  	/* 
  	 * Inside the sysfs directory for the device there is a symlink
  	 * to the directory representing the driver module, that path
  	 * happens to hold the name of the driver.
  	 *
  	 * So lets get the symlink for the drm device. Then read the link
  	 * and filter out the last directory which happens to be the name
  	 * of the driver, which we can use to load the correct interface.
  	 *
  	 * Thanks to Ray Strode of Plymouth for the code.
  	 */
  
  	ret = fstat(fd, &buffer);
  	if (ret)
  		return -EINVAL;
  
  	if (!S_ISCHR(buffer.st_mode))
  		return -EINVAL;
  
  	maj = major(buffer.st_rdev);
  	min = minor(buffer.st_rdev);
  
  	snprintf(path, PATH_SIZE, "/sys/dev/char/%d:%d/device/driver", maj, min);
  
  	if (readlink(path, link, PATH_SIZE) < 0)
  		return -EINVAL;
  
  	/* link looks something like this: ../../../bus/pci/drivers/intel */
  	slash_name = strrchr(link, '/');
  	if (!slash_name)
  		return -EINVAL;
  
  	/* copy name and at the same time remove the slash */
  	*out = strdup(slash_name + 1);
  	return 0;
  }
  
  static int
  linux_from_sysfs(int fd, struct kms_driver **out)
  {
  	char *name;
  	int ret;
  
  	ret = linux_name_from_sysfs(fd, &name);
  	if (ret)
  		return ret;
  
  #if HAVE_INTEL
  	if (!strcmp(name, "intel"))
  		ret = intel_create(fd, out);
  	else
  #endif
  #if HAVE_VMWGFX
  	if (!strcmp(name, "vmwgfx"))
  		ret = vmwgfx_create(fd, out);
  	else
  #endif
  #if HAVE_NOUVEAU
  	if (!strcmp(name, "nouveau"))
  		ret = nouveau_create(fd, out);
  	else
  #endif
  #if HAVE_RADEON
  	if (!strcmp(name, "radeon"))
  		ret = radeon_create(fd, out);
  	else
  #endif
  #if HAVE_EXYNOS
  	if (!strcmp(name, "exynos"))
  		ret = exynos_create(fd, out);
  	else
  #endif
  		ret = -ENOSYS;
  
  	free(name);
  	return ret;
  }
  
  drm_private int
  linux_create(int fd, struct kms_driver **out)
  {
  	if (!dumb_create(fd, out))
  		return 0;
  
  	return linux_from_sysfs(fd, out);
  }