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authorEric Anholt <eric@anholt.net>2007-07-19 06:17:58 -0700
committerEric Anholt <eric@anholt.net>2007-07-19 06:17:58 -0700
commite544286eae71a6b150af4d86096895c14e42c36e (patch)
tree3b2d72d56fab0687290506944691e041821c8cea /linux-core/xgi_drm.h
parentecf3fbe599cd72c495acf339ae24f3a9e01fdb36 (diff)
FreeBSD: Fix the recently added drawable add/remove/update code.
Diffstat (limited to 'linux-core/xgi_drm.h')
0 files changed, 0 insertions, 0 deletions
generated by cgit v1.2.3 (git 2.25.1) at 2025-11-19 19:31:14 +0000
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/* lock.c -- IOCTLs for locking -*- linux-c -*-
 * Created: Tue Feb  2 08:37:54 1999 by faith@valinux.com
 */
/*-
 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
 * 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, sublicense,
 * 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 NONINFRINGEMENT.  IN NO EVENT SHALL
 * VA LINUX SYSTEMS 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.
 *
 * Authors:
 *    Rickard E. (Rik) Faith <faith@valinux.com>
 *    Gareth Hughes <gareth@valinux.com>
 *
 */

#include "drmP.h"

int drm_lock_take(__volatile__ unsigned int *lock, unsigned int context)
{
	unsigned int old, new;

	do {
		old = *lock;
		if (old & _DRM_LOCK_HELD) new = old | _DRM_LOCK_CONT;
		else			  new = context | _DRM_LOCK_HELD;
	} while (!atomic_cmpset_int(lock, old, new));

	if (_DRM_LOCKING_CONTEXT(old) == context) {
		if (old & _DRM_LOCK_HELD) {
			if (context != DRM_KERNEL_CONTEXT) {
				DRM_ERROR("%d holds heavyweight lock\n",
					  context);
			}
			return 0;
		}
	}
	if (new == (context | _DRM_LOCK_HELD)) {
				/* Have lock */
		return 1;
	}
	return 0;
}

/* This takes a lock forcibly and hands it to context.	Should ONLY be used