Doug / smarc-fsl-linux-kernel

Download as
Browse Code ยป

Commit 45ff46c54a31bf8924b61e3e3411654410a3b5c3

Authored by Daniel Vetter
Committed by Dave Airlie
1 parent 4a445f291a
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

drm: readd drm_lock_free in drm_unlock 

I've accidently killed a little bit too much in

commit 1da3f87ebb7edb3e0b829ec4bbe5fb3d9d93986f
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Mon Aug 23 22:53:24 2010 +0200

    drm: kill kernel_context_switch callbacks

Note to self: Next time also test with AIGLX disabled.

Reported-and-Tested-by: Andy Furniss <lists@andyfurniss.entadsl.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=30374
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Showing 1 changed file with 5 additions and 0 deletions Inline Diff

drivers/gpu/drm/drm_lock.c
Diff comments   View file @ 45ff46c
1 /** 1 /**
2 * \file drm_lock.c 2 * \file drm_lock.c
3 * IOCTLs for locking 3 * IOCTLs for locking
4 * 4 *
5 * \author Rickard E. (Rik) Faith <faith@valinux.com> 5 * \author Rickard E. (Rik) Faith <faith@valinux.com>
6 * \author Gareth Hughes <gareth@valinux.com> 6 * \author Gareth Hughes <gareth@valinux.com>
7 */ 7 */
8 8
9 /* 9 /*
10 * Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com 10 * Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
11 * 11 *
12 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas. 12 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
13 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California. 13 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
14 * All Rights Reserved. 14 * All Rights Reserved.
15 * 15 *
16 * Permission is hereby granted, free of charge, to any person obtaining a 16 * Permission is hereby granted, free of charge, to any person obtaining a
17 * copy of this software and associated documentation files (the "Software"), 17 * copy of this software and associated documentation files (the "Software"),
18 * to deal in the Software without restriction, including without limitation 18 * to deal in the Software without restriction, including without limitation
19 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 19 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
20 * and/or sell copies of the Software, and to permit persons to whom the 20 * and/or sell copies of the Software, and to permit persons to whom the
21 * Software is furnished to do so, subject to the following conditions: 21 * Software is furnished to do so, subject to the following conditions:
22 * 22 *
23 * The above copyright notice and this permission notice (including the next 23 * The above copyright notice and this permission notice (including the next
24 * paragraph) shall be included in all copies or substantial portions of the 24 * paragraph) shall be included in all copies or substantial portions of the
25 * Software. 25 * Software.
26 * 26 *
27 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 27 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
28 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 28 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
29 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 29 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
30 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 30 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
31 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 31 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
32 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 32 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
33 * OTHER DEALINGS IN THE SOFTWARE. 33 * OTHER DEALINGS IN THE SOFTWARE.
34 */ 34 */
35 35
36 #include "drmP.h" 36 #include "drmP.h"
37 37
38 static int drm_notifier(void *priv); 38 static int drm_notifier(void *priv);
39 39
40 static int drm_lock_take(struct drm_lock_data *lock_data, unsigned int context); 40 static int drm_lock_take(struct drm_lock_data *lock_data, unsigned int context);
41 41
42 /** 42 /**
43 * Lock ioctl. 43 * Lock ioctl.
44 * 44 *
45 * \param inode device inode. 45 * \param inode device inode.
46 * \param file_priv DRM file private. 46 * \param file_priv DRM file private.
47 * \param cmd command. 47 * \param cmd command.
48 * \param arg user argument, pointing to a drm_lock structure. 48 * \param arg user argument, pointing to a drm_lock structure.
49 * \return zero on success or negative number on failure. 49 * \return zero on success or negative number on failure.
50 * 50 *
51 * Add the current task to the lock wait queue, and attempt to take to lock. 51 * Add the current task to the lock wait queue, and attempt to take to lock.
52 */ 52 */
53 int drm_lock(struct drm_device *dev, void *data, struct drm_file *file_priv) 53 int drm_lock(struct drm_device *dev, void *data, struct drm_file *file_priv)
54 { 54 {
55 DECLARE_WAITQUEUE(entry, current); 55 DECLARE_WAITQUEUE(entry, current);
56 struct drm_lock *lock = data; 56 struct drm_lock *lock = data;
57 struct drm_master *master = file_priv->master; 57 struct drm_master *master = file_priv->master;
58 int ret = 0; 58 int ret = 0;
59 59
60 ++file_priv->lock_count; 60 ++file_priv->lock_count;
61 61
62 if (lock->context == DRM_KERNEL_CONTEXT) { 62 if (lock->context == DRM_KERNEL_CONTEXT) {
63 DRM_ERROR("Process %d using kernel context %d\n", 63 DRM_ERROR("Process %d using kernel context %d\n",
64 task_pid_nr(current), lock->context); 64 task_pid_nr(current), lock->context);
65 return -EINVAL; 65 return -EINVAL;
66 } 66 }
67 67
68 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n", 68 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
69 lock->context, task_pid_nr(current), 69 lock->context, task_pid_nr(current),
70 master->lock.hw_lock->lock, lock->flags); 70 master->lock.hw_lock->lock, lock->flags);
71 71
72 if (drm_core_check_feature(dev, DRIVER_DMA_QUEUE)) 72 if (drm_core_check_feature(dev, DRIVER_DMA_QUEUE))
73 if (lock->context < 0) 73 if (lock->context < 0)
74 return -EINVAL; 74 return -EINVAL;
75 75
76 add_wait_queue(&master->lock.lock_queue, &entry); 76 add_wait_queue(&master->lock.lock_queue, &entry);
77 spin_lock_bh(&master->lock.spinlock); 77 spin_lock_bh(&master->lock.spinlock);
78 master->lock.user_waiters++; 78 master->lock.user_waiters++;
79 spin_unlock_bh(&master->lock.spinlock); 79 spin_unlock_bh(&master->lock.spinlock);
80 80
81 for (;;) { 81 for (;;) {
82 __set_current_state(TASK_INTERRUPTIBLE); 82 __set_current_state(TASK_INTERRUPTIBLE);
83 if (!master->lock.hw_lock) { 83 if (!master->lock.hw_lock) {
84 /* Device has been unregistered */ 84 /* Device has been unregistered */
85 send_sig(SIGTERM, current, 0); 85 send_sig(SIGTERM, current, 0);
86 ret = -EINTR; 86 ret = -EINTR;
87 break; 87 break;
88 } 88 }
89 if (drm_lock_take(&master->lock, lock->context)) { 89 if (drm_lock_take(&master->lock, lock->context)) {
90 master->lock.file_priv = file_priv; 90 master->lock.file_priv = file_priv;
91 master->lock.lock_time = jiffies; 91 master->lock.lock_time = jiffies;
92 atomic_inc(&dev->counts[_DRM_STAT_LOCKS]); 92 atomic_inc(&dev->counts[_DRM_STAT_LOCKS]);
93 break; /* Got lock */ 93 break; /* Got lock */
94 } 94 }
95 95
96 /* Contention */ 96 /* Contention */
97 mutex_unlock(&drm_global_mutex); 97 mutex_unlock(&drm_global_mutex);
98 schedule(); 98 schedule();
99 mutex_lock(&drm_global_mutex); 99 mutex_lock(&drm_global_mutex);
100 if (signal_pending(current)) { 100 if (signal_pending(current)) {
101 ret = -EINTR; 101 ret = -EINTR;
102 break; 102 break;
103 } 103 }
104 } 104 }
105 spin_lock_bh(&master->lock.spinlock); 105 spin_lock_bh(&master->lock.spinlock);
106 master->lock.user_waiters--; 106 master->lock.user_waiters--;
107 spin_unlock_bh(&master->lock.spinlock); 107 spin_unlock_bh(&master->lock.spinlock);
108 __set_current_state(TASK_RUNNING); 108 __set_current_state(TASK_RUNNING);
109 remove_wait_queue(&master->lock.lock_queue, &entry); 109 remove_wait_queue(&master->lock.lock_queue, &entry);
110 110
111 DRM_DEBUG("%d %s\n", lock->context, 111 DRM_DEBUG("%d %s\n", lock->context,
112 ret ? "interrupted" : "has lock"); 112 ret ? "interrupted" : "has lock");
113 if (ret) return ret; 113 if (ret) return ret;
114 114
115 /* don't set the block all signals on the master process for now 115 /* don't set the block all signals on the master process for now
116 * really probably not the correct answer but lets us debug xkb 116 * really probably not the correct answer but lets us debug xkb
117 * xserver for now */ 117 * xserver for now */
118 if (!file_priv->is_master) { 118 if (!file_priv->is_master) {
119 sigemptyset(&dev->sigmask); 119 sigemptyset(&dev->sigmask);
120 sigaddset(&dev->sigmask, SIGSTOP); 120 sigaddset(&dev->sigmask, SIGSTOP);
121 sigaddset(&dev->sigmask, SIGTSTP); 121 sigaddset(&dev->sigmask, SIGTSTP);
122 sigaddset(&dev->sigmask, SIGTTIN); 122 sigaddset(&dev->sigmask, SIGTTIN);
123 sigaddset(&dev->sigmask, SIGTTOU); 123 sigaddset(&dev->sigmask, SIGTTOU);
124 dev->sigdata.context = lock->context; 124 dev->sigdata.context = lock->context;
125 dev->sigdata.lock = master->lock.hw_lock; 125 dev->sigdata.lock = master->lock.hw_lock;
126 block_all_signals(drm_notifier, &dev->sigdata, &dev->sigmask); 126 block_all_signals(drm_notifier, &dev->sigdata, &dev->sigmask);
127 } 127 }
128 128
129 if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT)) 129 if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT))
130 { 130 {
131 if (dev->driver->dma_quiescent(dev)) { 131 if (dev->driver->dma_quiescent(dev)) {
132 DRM_DEBUG("%d waiting for DMA quiescent\n", 132 DRM_DEBUG("%d waiting for DMA quiescent\n",
133 lock->context); 133 lock->context);
134 return -EBUSY; 134 return -EBUSY;
135 } 135 }
136 } 136 }
137 137
138 return 0; 138 return 0;
139 } 139 }
140 140
141 /** 141 /**
142 * Unlock ioctl. 142 * Unlock ioctl.
143 * 143 *
144 * \param inode device inode. 144 * \param inode device inode.
145 * \param file_priv DRM file private. 145 * \param file_priv DRM file private.
146 * \param cmd command. 146 * \param cmd command.
147 * \param arg user argument, pointing to a drm_lock structure. 147 * \param arg user argument, pointing to a drm_lock structure.
148 * \return zero on success or negative number on failure. 148 * \return zero on success or negative number on failure.
149 * 149 *
150 * Transfer and free the lock. 150 * Transfer and free the lock.
151 */ 151 */
152 int drm_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv) 152 int drm_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv)
153 { 153 {
154 struct drm_lock *lock = data; 154 struct drm_lock *lock = data;
155 struct drm_master *master = file_priv->master;
155 156
156 if (lock->context == DRM_KERNEL_CONTEXT) { 157 if (lock->context == DRM_KERNEL_CONTEXT) {
157 DRM_ERROR("Process %d using kernel context %d\n", 158 DRM_ERROR("Process %d using kernel context %d\n",
158 task_pid_nr(current), lock->context); 159 task_pid_nr(current), lock->context);
159 return -EINVAL; 160 return -EINVAL;
160 } 161 }
161 162
162 atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]); 163 atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]);
164
165 if (drm_lock_free(&master->lock, lock->context)) {
166 /* FIXME: Should really bail out here. */
167 }
163 168
164 unblock_all_signals(); 169 unblock_all_signals();
165 return 0; 170 return 0;
166 } 171 }
167 172
168 /** 173 /**
169 * Take the heavyweight lock. 174 * Take the heavyweight lock.
170 * 175 *
171 * \param lock lock pointer. 176 * \param lock lock pointer.
172 * \param context locking context. 177 * \param context locking context.
173 * \return one if the lock is held, or zero otherwise. 178 * \return one if the lock is held, or zero otherwise.
174 * 179 *
175 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction. 180 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
176 */ 181 */
177 static 182 static
178 int drm_lock_take(struct drm_lock_data *lock_data, 183 int drm_lock_take(struct drm_lock_data *lock_data,
179 unsigned int context) 184 unsigned int context)
180 { 185 {
181 unsigned int old, new, prev; 186 unsigned int old, new, prev;
182 volatile unsigned int *lock = &lock_data->hw_lock->lock; 187 volatile unsigned int *lock = &lock_data->hw_lock->lock;
183 188
184 spin_lock_bh(&lock_data->spinlock); 189 spin_lock_bh(&lock_data->spinlock);
185 do { 190 do {
186 old = *lock; 191 old = *lock;
187 if (old & _DRM_LOCK_HELD) 192 if (old & _DRM_LOCK_HELD)
188 new = old | _DRM_LOCK_CONT; 193 new = old | _DRM_LOCK_CONT;
189 else { 194 else {
190 new = context | _DRM_LOCK_HELD | 195 new = context | _DRM_LOCK_HELD |
191 ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ? 196 ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ?
192 _DRM_LOCK_CONT : 0); 197 _DRM_LOCK_CONT : 0);
193 } 198 }
194 prev = cmpxchg(lock, old, new); 199 prev = cmpxchg(lock, old, new);
195 } while (prev != old); 200 } while (prev != old);
196 spin_unlock_bh(&lock_data->spinlock); 201 spin_unlock_bh(&lock_data->spinlock);
197 202
198 if (_DRM_LOCKING_CONTEXT(old) == context) { 203 if (_DRM_LOCKING_CONTEXT(old) == context) {
199 if (old & _DRM_LOCK_HELD) { 204 if (old & _DRM_LOCK_HELD) {
200 if (context != DRM_KERNEL_CONTEXT) { 205 if (context != DRM_KERNEL_CONTEXT) {
201 DRM_ERROR("%d holds heavyweight lock\n", 206 DRM_ERROR("%d holds heavyweight lock\n",
202 context); 207 context);
203 } 208 }
204 return 0; 209 return 0;
205 } 210 }
206 } 211 }
207 212
208 if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) { 213 if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) {
209 /* Have lock */ 214 /* Have lock */
210 return 1; 215 return 1;
211 } 216 }
212 return 0; 217 return 0;
213 } 218 }
214 219
215 /** 220 /**
216 * This takes a lock forcibly and hands it to context. Should ONLY be used 221 * This takes a lock forcibly and hands it to context. Should ONLY be used
217 * inside *_unlock to give lock to kernel before calling *_dma_schedule. 222 * inside *_unlock to give lock to kernel before calling *_dma_schedule.
218 * 223 *
219 * \param dev DRM device. 224 * \param dev DRM device.
220 * \param lock lock pointer. 225 * \param lock lock pointer.
221 * \param context locking context. 226 * \param context locking context.
222 * \return always one. 227 * \return always one.
223 * 228 *
224 * Resets the lock file pointer. 229 * Resets the lock file pointer.
225 * Marks the lock as held by the given context, via the \p cmpxchg instruction. 230 * Marks the lock as held by the given context, via the \p cmpxchg instruction.
226 */ 231 */
227 static int drm_lock_transfer(struct drm_lock_data *lock_data, 232 static int drm_lock_transfer(struct drm_lock_data *lock_data,
228 unsigned int context) 233 unsigned int context)
229 { 234 {
230 unsigned int old, new, prev; 235 unsigned int old, new, prev;
231 volatile unsigned int *lock = &lock_data->hw_lock->lock; 236 volatile unsigned int *lock = &lock_data->hw_lock->lock;
232 237
233 lock_data->file_priv = NULL; 238 lock_data->file_priv = NULL;
234 do { 239 do {
235 old = *lock; 240 old = *lock;
236 new = context | _DRM_LOCK_HELD; 241 new = context | _DRM_LOCK_HELD;
237 prev = cmpxchg(lock, old, new); 242 prev = cmpxchg(lock, old, new);
238 } while (prev != old); 243 } while (prev != old);
239 return 1; 244 return 1;
240 } 245 }
241 246
242 /** 247 /**
243 * Free lock. 248 * Free lock.
244 * 249 *
245 * \param dev DRM device. 250 * \param dev DRM device.
246 * \param lock lock. 251 * \param lock lock.
247 * \param context context. 252 * \param context context.
248 * 253 *
249 * Resets the lock file pointer. 254 * Resets the lock file pointer.
250 * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task 255 * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task
251 * waiting on the lock queue. 256 * waiting on the lock queue.
252 */ 257 */
253 int drm_lock_free(struct drm_lock_data *lock_data, unsigned int context) 258 int drm_lock_free(struct drm_lock_data *lock_data, unsigned int context)
254 { 259 {
255 unsigned int old, new, prev; 260 unsigned int old, new, prev;
256 volatile unsigned int *lock = &lock_data->hw_lock->lock; 261 volatile unsigned int *lock = &lock_data->hw_lock->lock;
257 262
258 spin_lock_bh(&lock_data->spinlock); 263 spin_lock_bh(&lock_data->spinlock);
259 if (lock_data->kernel_waiters != 0) { 264 if (lock_data->kernel_waiters != 0) {
260 drm_lock_transfer(lock_data, 0); 265 drm_lock_transfer(lock_data, 0);
261 lock_data->idle_has_lock = 1; 266 lock_data->idle_has_lock = 1;
262 spin_unlock_bh(&lock_data->spinlock); 267 spin_unlock_bh(&lock_data->spinlock);
263 return 1; 268 return 1;
264 } 269 }
265 spin_unlock_bh(&lock_data->spinlock); 270 spin_unlock_bh(&lock_data->spinlock);
266 271
267 do { 272 do {
268 old = *lock; 273 old = *lock;
269 new = _DRM_LOCKING_CONTEXT(old); 274 new = _DRM_LOCKING_CONTEXT(old);
270 prev = cmpxchg(lock, old, new); 275 prev = cmpxchg(lock, old, new);
271 } while (prev != old); 276 } while (prev != old);
272 277
273 if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) { 278 if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
274 DRM_ERROR("%d freed heavyweight lock held by %d\n", 279 DRM_ERROR("%d freed heavyweight lock held by %d\n",
275 context, _DRM_LOCKING_CONTEXT(old)); 280 context, _DRM_LOCKING_CONTEXT(old));
276 return 1; 281 return 1;
277 } 282 }
278 wake_up_interruptible(&lock_data->lock_queue); 283 wake_up_interruptible(&lock_data->lock_queue);
279 return 0; 284 return 0;
280 } 285 }
281 286
282 /** 287 /**
283 * If we get here, it means that the process has called DRM_IOCTL_LOCK 288 * If we get here, it means that the process has called DRM_IOCTL_LOCK
284 * without calling DRM_IOCTL_UNLOCK. 289 * without calling DRM_IOCTL_UNLOCK.
285 * 290 *
286 * If the lock is not held, then let the signal proceed as usual. If the lock 291 * If the lock is not held, then let the signal proceed as usual. If the lock
287 * is held, then set the contended flag and keep the signal blocked. 292 * is held, then set the contended flag and keep the signal blocked.
288 * 293 *
289 * \param priv pointer to a drm_sigdata structure. 294 * \param priv pointer to a drm_sigdata structure.
290 * \return one if the signal should be delivered normally, or zero if the 295 * \return one if the signal should be delivered normally, or zero if the
291 * signal should be blocked. 296 * signal should be blocked.
292 */ 297 */
293 static int drm_notifier(void *priv) 298 static int drm_notifier(void *priv)
294 { 299 {
295 struct drm_sigdata *s = (struct drm_sigdata *) priv; 300 struct drm_sigdata *s = (struct drm_sigdata *) priv;
296 unsigned int old, new, prev; 301 unsigned int old, new, prev;
297 302
298 /* Allow signal delivery if lock isn't held */ 303 /* Allow signal delivery if lock isn't held */
299 if (!s->lock || !_DRM_LOCK_IS_HELD(s->lock->lock) 304 if (!s->lock || !_DRM_LOCK_IS_HELD(s->lock->lock)
300 || _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context) 305 || _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context)
301 return 1; 306 return 1;
302 307
303 /* Otherwise, set flag to force call to 308 /* Otherwise, set flag to force call to
304 drmUnlock */ 309 drmUnlock */
305 do { 310 do {
306 old = s->lock->lock; 311 old = s->lock->lock;
307 new = old | _DRM_LOCK_CONT; 312 new = old | _DRM_LOCK_CONT;
308 prev = cmpxchg(&s->lock->lock, old, new); 313 prev = cmpxchg(&s->lock->lock, old, new);
309 } while (prev != old); 314 } while (prev != old);
310 return 0; 315 return 0;
311 } 316 }
312 317
313 /** 318 /**
314 * This function returns immediately and takes the hw lock 319 * This function returns immediately and takes the hw lock
315 * with the kernel context if it is free, otherwise it gets the highest priority when and if 320 * with the kernel context if it is free, otherwise it gets the highest priority when and if
316 * it is eventually released. 321 * it is eventually released.
317 * 322 *
318 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held 323 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
319 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause 324 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
320 * a deadlock, which is why the "idlelock" was invented). 325 * a deadlock, which is why the "idlelock" was invented).
321 * 326 *
322 * This should be sufficient to wait for GPU idle without 327 * This should be sufficient to wait for GPU idle without
323 * having to worry about starvation. 328 * having to worry about starvation.
324 */ 329 */
325 330
326 void drm_idlelock_take(struct drm_lock_data *lock_data) 331 void drm_idlelock_take(struct drm_lock_data *lock_data)
327 { 332 {
328 int ret = 0; 333 int ret = 0;
329 334
330 spin_lock_bh(&lock_data->spinlock); 335 spin_lock_bh(&lock_data->spinlock);
331 lock_data->kernel_waiters++; 336 lock_data->kernel_waiters++;
332 if (!lock_data->idle_has_lock) { 337 if (!lock_data->idle_has_lock) {
333 338
334 spin_unlock_bh(&lock_data->spinlock); 339 spin_unlock_bh(&lock_data->spinlock);
335 ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT); 340 ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT);
336 spin_lock_bh(&lock_data->spinlock); 341 spin_lock_bh(&lock_data->spinlock);
337 342
338 if (ret == 1) 343 if (ret == 1)
339 lock_data->idle_has_lock = 1; 344 lock_data->idle_has_lock = 1;
340 } 345 }
341 spin_unlock_bh(&lock_data->spinlock); 346 spin_unlock_bh(&lock_data->spinlock);
342 } 347 }
343 348
344 void drm_idlelock_release(struct drm_lock_data *lock_data) 349 void drm_idlelock_release(struct drm_lock_data *lock_data)
345 { 350 {
346 unsigned int old, prev; 351 unsigned int old, prev;
347 volatile unsigned int *lock = &lock_data->hw_lock->lock; 352 volatile unsigned int *lock = &lock_data->hw_lock->lock;
348 353
349 spin_lock_bh(&lock_data->spinlock); 354 spin_lock_bh(&lock_data->spinlock);
350 if (--lock_data->kernel_waiters == 0) { 355 if (--lock_data->kernel_waiters == 0) {
351 if (lock_data->idle_has_lock) { 356 if (lock_data->idle_has_lock) {
352 do { 357 do {
353 old = *lock; 358 old = *lock;
354 prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT); 359 prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT);
355 } while (prev != old); 360 } while (prev != old);
356 wake_up_interruptible(&lock_data->lock_queue); 361 wake_up_interruptible(&lock_data->lock_queue);
357 lock_data->idle_has_lock = 0; 362 lock_data->idle_has_lock = 0;
358 } 363 }
359 } 364 }
360 spin_unlock_bh(&lock_data->spinlock); 365 spin_unlock_bh(&lock_data->spinlock);
361 } 366 }
362 367
363 int drm_i_have_hw_lock(struct drm_device *dev, struct drm_file *file_priv) 368 int drm_i_have_hw_lock(struct drm_device *dev, struct drm_file *file_priv)
364 { 369 {
365 struct drm_master *master = file_priv->master; 370 struct drm_master *master = file_priv->master;
366 return (file_priv->lock_count && master->lock.hw_lock && 371 return (file_priv->lock_count && master->lock.hw_lock &&
367 _DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) && 372 _DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) &&
368 master->lock.file_priv == file_priv); 373 master->lock.file_priv == file_priv);
369 } 374 }
370 375