xref: /openbmc/linux/drivers/gpu/drm/i915/i915_irq.c (revision 384740dc)
1 /* i915_irq.c -- IRQ support for the I915 -*- linux-c -*-
2  */
3 /*
4  * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
5  * All Rights Reserved.
6  *
7  * Permission is hereby granted, free of charge, to any person obtaining a
8  * copy of this software and associated documentation files (the
9  * "Software"), to deal in the Software without restriction, including
10  * without limitation the rights to use, copy, modify, merge, publish,
11  * distribute, sub license, and/or sell copies of the Software, and to
12  * permit persons to whom the Software is furnished to do so, subject to
13  * the following conditions:
14  *
15  * The above copyright notice and this permission notice (including the
16  * next paragraph) shall be included in all copies or substantial portions
17  * of the Software.
18  *
19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
20  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
21  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
22  * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
23  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
24  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
25  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
26  *
27  */
28 
29 #include "drmP.h"
30 #include "drm.h"
31 #include "i915_drm.h"
32 #include "i915_drv.h"
33 
34 #define USER_INT_FLAG (1<<1)
35 #define VSYNC_PIPEB_FLAG (1<<5)
36 #define VSYNC_PIPEA_FLAG (1<<7)
37 
38 #define MAX_NOPID ((u32)~0)
39 
40 /**
41  * Emit blits for scheduled buffer swaps.
42  *
43  * This function will be called with the HW lock held.
44  */
45 static void i915_vblank_tasklet(struct drm_device *dev)
46 {
47 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
48 	unsigned long irqflags;
49 	struct list_head *list, *tmp, hits, *hit;
50 	int nhits, nrects, slice[2], upper[2], lower[2], i;
51 	unsigned counter[2] = { atomic_read(&dev->vbl_received),
52 				atomic_read(&dev->vbl_received2) };
53 	struct drm_drawable_info *drw;
54 	drm_i915_sarea_t *sarea_priv = dev_priv->sarea_priv;
55 	u32 cpp = dev_priv->cpp;
56 	u32 cmd = (cpp == 4) ? (XY_SRC_COPY_BLT_CMD |
57 				XY_SRC_COPY_BLT_WRITE_ALPHA |
58 				XY_SRC_COPY_BLT_WRITE_RGB)
59 			     : XY_SRC_COPY_BLT_CMD;
60 	u32 src_pitch = sarea_priv->pitch * cpp;
61 	u32 dst_pitch = sarea_priv->pitch * cpp;
62 	u32 ropcpp = (0xcc << 16) | ((cpp - 1) << 24);
63 	RING_LOCALS;
64 
65 	if (IS_I965G(dev) && sarea_priv->front_tiled) {
66 		cmd |= XY_SRC_COPY_BLT_DST_TILED;
67 		dst_pitch >>= 2;
68 	}
69 	if (IS_I965G(dev) && sarea_priv->back_tiled) {
70 		cmd |= XY_SRC_COPY_BLT_SRC_TILED;
71 		src_pitch >>= 2;
72 	}
73 
74 	DRM_DEBUG("\n");
75 
76 	INIT_LIST_HEAD(&hits);
77 
78 	nhits = nrects = 0;
79 
80 	spin_lock_irqsave(&dev_priv->swaps_lock, irqflags);
81 
82 	/* Find buffer swaps scheduled for this vertical blank */
83 	list_for_each_safe(list, tmp, &dev_priv->vbl_swaps.head) {
84 		drm_i915_vbl_swap_t *vbl_swap =
85 			list_entry(list, drm_i915_vbl_swap_t, head);
86 
87 		if ((counter[vbl_swap->pipe] - vbl_swap->sequence) > (1<<23))
88 			continue;
89 
90 		list_del(list);
91 		dev_priv->swaps_pending--;
92 
93 		spin_unlock(&dev_priv->swaps_lock);
94 		spin_lock(&dev->drw_lock);
95 
96 		drw = drm_get_drawable_info(dev, vbl_swap->drw_id);
97 
98 		if (!drw) {
99 			spin_unlock(&dev->drw_lock);
100 			drm_free(vbl_swap, sizeof(*vbl_swap), DRM_MEM_DRIVER);
101 			spin_lock(&dev_priv->swaps_lock);
102 			continue;
103 		}
104 
105 		list_for_each(hit, &hits) {
106 			drm_i915_vbl_swap_t *swap_cmp =
107 				list_entry(hit, drm_i915_vbl_swap_t, head);
108 			struct drm_drawable_info *drw_cmp =
109 				drm_get_drawable_info(dev, swap_cmp->drw_id);
110 
111 			if (drw_cmp &&
112 			    drw_cmp->rects[0].y1 > drw->rects[0].y1) {
113 				list_add_tail(list, hit);
114 				break;
115 			}
116 		}
117 
118 		spin_unlock(&dev->drw_lock);
119 
120 		/* List of hits was empty, or we reached the end of it */
121 		if (hit == &hits)
122 			list_add_tail(list, hits.prev);
123 
124 		nhits++;
125 
126 		spin_lock(&dev_priv->swaps_lock);
127 	}
128 
129 	if (nhits == 0) {
130 		spin_unlock_irqrestore(&dev_priv->swaps_lock, irqflags);
131 		return;
132 	}
133 
134 	spin_unlock(&dev_priv->swaps_lock);
135 
136 	i915_kernel_lost_context(dev);
137 
138 	if (IS_I965G(dev)) {
139 		BEGIN_LP_RING(4);
140 
141 		OUT_RING(GFX_OP_DRAWRECT_INFO_I965);
142 		OUT_RING(0);
143 		OUT_RING(((sarea_priv->width - 1) & 0xffff) | ((sarea_priv->height - 1) << 16));
144 		OUT_RING(0);
145 		ADVANCE_LP_RING();
146 	} else {
147 		BEGIN_LP_RING(6);
148 
149 		OUT_RING(GFX_OP_DRAWRECT_INFO);
150 		OUT_RING(0);
151 		OUT_RING(0);
152 		OUT_RING(sarea_priv->width | sarea_priv->height << 16);
153 		OUT_RING(sarea_priv->width | sarea_priv->height << 16);
154 		OUT_RING(0);
155 
156 		ADVANCE_LP_RING();
157 	}
158 
159 	sarea_priv->ctxOwner = DRM_KERNEL_CONTEXT;
160 
161 	upper[0] = upper[1] = 0;
162 	slice[0] = max(sarea_priv->pipeA_h / nhits, 1);
163 	slice[1] = max(sarea_priv->pipeB_h / nhits, 1);
164 	lower[0] = sarea_priv->pipeA_y + slice[0];
165 	lower[1] = sarea_priv->pipeB_y + slice[0];
166 
167 	spin_lock(&dev->drw_lock);
168 
169 	/* Emit blits for buffer swaps, partitioning both outputs into as many
170 	 * slices as there are buffer swaps scheduled in order to avoid tearing
171 	 * (based on the assumption that a single buffer swap would always
172 	 * complete before scanout starts).
173 	 */
174 	for (i = 0; i++ < nhits;
175 	     upper[0] = lower[0], lower[0] += slice[0],
176 	     upper[1] = lower[1], lower[1] += slice[1]) {
177 		if (i == nhits)
178 			lower[0] = lower[1] = sarea_priv->height;
179 
180 		list_for_each(hit, &hits) {
181 			drm_i915_vbl_swap_t *swap_hit =
182 				list_entry(hit, drm_i915_vbl_swap_t, head);
183 			struct drm_clip_rect *rect;
184 			int num_rects, pipe;
185 			unsigned short top, bottom;
186 
187 			drw = drm_get_drawable_info(dev, swap_hit->drw_id);
188 
189 			if (!drw)
190 				continue;
191 
192 			rect = drw->rects;
193 			pipe = swap_hit->pipe;
194 			top = upper[pipe];
195 			bottom = lower[pipe];
196 
197 			for (num_rects = drw->num_rects; num_rects--; rect++) {
198 				int y1 = max(rect->y1, top);
199 				int y2 = min(rect->y2, bottom);
200 
201 				if (y1 >= y2)
202 					continue;
203 
204 				BEGIN_LP_RING(8);
205 
206 				OUT_RING(cmd);
207 				OUT_RING(ropcpp | dst_pitch);
208 				OUT_RING((y1 << 16) | rect->x1);
209 				OUT_RING((y2 << 16) | rect->x2);
210 				OUT_RING(sarea_priv->front_offset);
211 				OUT_RING((y1 << 16) | rect->x1);
212 				OUT_RING(src_pitch);
213 				OUT_RING(sarea_priv->back_offset);
214 
215 				ADVANCE_LP_RING();
216 			}
217 		}
218 	}
219 
220 	spin_unlock_irqrestore(&dev->drw_lock, irqflags);
221 
222 	list_for_each_safe(hit, tmp, &hits) {
223 		drm_i915_vbl_swap_t *swap_hit =
224 			list_entry(hit, drm_i915_vbl_swap_t, head);
225 
226 		list_del(hit);
227 
228 		drm_free(swap_hit, sizeof(*swap_hit), DRM_MEM_DRIVER);
229 	}
230 }
231 
232 irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
233 {
234 	struct drm_device *dev = (struct drm_device *) arg;
235 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
236 	u16 temp;
237 	u32 pipea_stats, pipeb_stats;
238 
239 	pipea_stats = I915_READ(I915REG_PIPEASTAT);
240 	pipeb_stats = I915_READ(I915REG_PIPEBSTAT);
241 
242 	temp = I915_READ16(I915REG_INT_IDENTITY_R);
243 
244 	temp &= (USER_INT_FLAG | VSYNC_PIPEA_FLAG | VSYNC_PIPEB_FLAG);
245 
246 	DRM_DEBUG("%s flag=%08x\n", __FUNCTION__, temp);
247 
248 	if (temp == 0)
249 		return IRQ_NONE;
250 
251 	I915_WRITE16(I915REG_INT_IDENTITY_R, temp);
252 	(void) I915_READ16(I915REG_INT_IDENTITY_R);
253 	DRM_READMEMORYBARRIER();
254 
255 	dev_priv->sarea_priv->last_dispatch = READ_BREADCRUMB(dev_priv);
256 
257 	if (temp & USER_INT_FLAG)
258 		DRM_WAKEUP(&dev_priv->irq_queue);
259 
260 	if (temp & (VSYNC_PIPEA_FLAG | VSYNC_PIPEB_FLAG)) {
261 		int vblank_pipe = dev_priv->vblank_pipe;
262 
263 		if ((vblank_pipe &
264 		     (DRM_I915_VBLANK_PIPE_A | DRM_I915_VBLANK_PIPE_B))
265 		    == (DRM_I915_VBLANK_PIPE_A | DRM_I915_VBLANK_PIPE_B)) {
266 			if (temp & VSYNC_PIPEA_FLAG)
267 				atomic_inc(&dev->vbl_received);
268 			if (temp & VSYNC_PIPEB_FLAG)
269 				atomic_inc(&dev->vbl_received2);
270 		} else if (((temp & VSYNC_PIPEA_FLAG) &&
271 			    (vblank_pipe & DRM_I915_VBLANK_PIPE_A)) ||
272 			   ((temp & VSYNC_PIPEB_FLAG) &&
273 			    (vblank_pipe & DRM_I915_VBLANK_PIPE_B)))
274 			atomic_inc(&dev->vbl_received);
275 
276 		DRM_WAKEUP(&dev->vbl_queue);
277 		drm_vbl_send_signals(dev);
278 
279 		if (dev_priv->swaps_pending > 0)
280 			drm_locked_tasklet(dev, i915_vblank_tasklet);
281 		I915_WRITE(I915REG_PIPEASTAT,
282 			pipea_stats|I915_VBLANK_INTERRUPT_ENABLE|
283 			I915_VBLANK_CLEAR);
284 		I915_WRITE(I915REG_PIPEBSTAT,
285 			pipeb_stats|I915_VBLANK_INTERRUPT_ENABLE|
286 			I915_VBLANK_CLEAR);
287 	}
288 
289 	return IRQ_HANDLED;
290 }
291 
292 static int i915_emit_irq(struct drm_device * dev)
293 {
294 	drm_i915_private_t *dev_priv = dev->dev_private;
295 	RING_LOCALS;
296 
297 	i915_kernel_lost_context(dev);
298 
299 	DRM_DEBUG("\n");
300 
301 	dev_priv->sarea_priv->last_enqueue = ++dev_priv->counter;
302 
303 	if (dev_priv->counter > 0x7FFFFFFFUL)
304 		dev_priv->sarea_priv->last_enqueue = dev_priv->counter = 1;
305 
306 	BEGIN_LP_RING(6);
307 	OUT_RING(CMD_STORE_DWORD_IDX);
308 	OUT_RING(20);
309 	OUT_RING(dev_priv->counter);
310 	OUT_RING(0);
311 	OUT_RING(0);
312 	OUT_RING(GFX_OP_USER_INTERRUPT);
313 	ADVANCE_LP_RING();
314 
315 	return dev_priv->counter;
316 }
317 
318 static int i915_wait_irq(struct drm_device * dev, int irq_nr)
319 {
320 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
321 	int ret = 0;
322 
323 	DRM_DEBUG("irq_nr=%d breadcrumb=%d\n", irq_nr,
324 		  READ_BREADCRUMB(dev_priv));
325 
326 	if (READ_BREADCRUMB(dev_priv) >= irq_nr)
327 		return 0;
328 
329 	dev_priv->sarea_priv->perf_boxes |= I915_BOX_WAIT;
330 
331 	DRM_WAIT_ON(ret, dev_priv->irq_queue, 3 * DRM_HZ,
332 		    READ_BREADCRUMB(dev_priv) >= irq_nr);
333 
334 	if (ret == -EBUSY) {
335 		DRM_ERROR("EBUSY -- rec: %d emitted: %d\n",
336 			  READ_BREADCRUMB(dev_priv), (int)dev_priv->counter);
337 	}
338 
339 	dev_priv->sarea_priv->last_dispatch = READ_BREADCRUMB(dev_priv);
340 	return ret;
341 }
342 
343 static int i915_driver_vblank_do_wait(struct drm_device *dev, unsigned int *sequence,
344 				      atomic_t *counter)
345 {
346 	drm_i915_private_t *dev_priv = dev->dev_private;
347 	unsigned int cur_vblank;
348 	int ret = 0;
349 
350 	if (!dev_priv) {
351 		DRM_ERROR("called with no initialization\n");
352 		return -EINVAL;
353 	}
354 
355 	DRM_WAIT_ON(ret, dev->vbl_queue, 3 * DRM_HZ,
356 		    (((cur_vblank = atomic_read(counter))
357 			- *sequence) <= (1<<23)));
358 
359 	*sequence = cur_vblank;
360 
361 	return ret;
362 }
363 
364 
365 int i915_driver_vblank_wait(struct drm_device *dev, unsigned int *sequence)
366 {
367 	return i915_driver_vblank_do_wait(dev, sequence, &dev->vbl_received);
368 }
369 
370 int i915_driver_vblank_wait2(struct drm_device *dev, unsigned int *sequence)
371 {
372 	return i915_driver_vblank_do_wait(dev, sequence, &dev->vbl_received2);
373 }
374 
375 /* Needs the lock as it touches the ring.
376  */
377 int i915_irq_emit(struct drm_device *dev, void *data,
378 			 struct drm_file *file_priv)
379 {
380 	drm_i915_private_t *dev_priv = dev->dev_private;
381 	drm_i915_irq_emit_t *emit = data;
382 	int result;
383 
384 	LOCK_TEST_WITH_RETURN(dev, file_priv);
385 
386 	if (!dev_priv) {
387 		DRM_ERROR("called with no initialization\n");
388 		return -EINVAL;
389 	}
390 
391 	result = i915_emit_irq(dev);
392 
393 	if (DRM_COPY_TO_USER(emit->irq_seq, &result, sizeof(int))) {
394 		DRM_ERROR("copy_to_user\n");
395 		return -EFAULT;
396 	}
397 
398 	return 0;
399 }
400 
401 /* Doesn't need the hardware lock.
402  */
403 int i915_irq_wait(struct drm_device *dev, void *data,
404 			 struct drm_file *file_priv)
405 {
406 	drm_i915_private_t *dev_priv = dev->dev_private;
407 	drm_i915_irq_wait_t *irqwait = data;
408 
409 	if (!dev_priv) {
410 		DRM_ERROR("called with no initialization\n");
411 		return -EINVAL;
412 	}
413 
414 	return i915_wait_irq(dev, irqwait->irq_seq);
415 }
416 
417 static void i915_enable_interrupt (struct drm_device *dev)
418 {
419 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
420 	u16 flag;
421 
422 	flag = 0;
423 	if (dev_priv->vblank_pipe & DRM_I915_VBLANK_PIPE_A)
424 		flag |= VSYNC_PIPEA_FLAG;
425 	if (dev_priv->vblank_pipe & DRM_I915_VBLANK_PIPE_B)
426 		flag |= VSYNC_PIPEB_FLAG;
427 
428 	I915_WRITE16(I915REG_INT_ENABLE_R, USER_INT_FLAG | flag);
429 }
430 
431 /* Set the vblank monitor pipe
432  */
433 int i915_vblank_pipe_set(struct drm_device *dev, void *data,
434 			 struct drm_file *file_priv)
435 {
436 	drm_i915_private_t *dev_priv = dev->dev_private;
437 	drm_i915_vblank_pipe_t *pipe = data;
438 
439 	if (!dev_priv) {
440 		DRM_ERROR("called with no initialization\n");
441 		return -EINVAL;
442 	}
443 
444 	if (pipe->pipe & ~(DRM_I915_VBLANK_PIPE_A|DRM_I915_VBLANK_PIPE_B)) {
445 		DRM_ERROR("called with invalid pipe 0x%x\n", pipe->pipe);
446 		return -EINVAL;
447 	}
448 
449 	dev_priv->vblank_pipe = pipe->pipe;
450 
451 	i915_enable_interrupt (dev);
452 
453 	return 0;
454 }
455 
456 int i915_vblank_pipe_get(struct drm_device *dev, void *data,
457 			 struct drm_file *file_priv)
458 {
459 	drm_i915_private_t *dev_priv = dev->dev_private;
460 	drm_i915_vblank_pipe_t *pipe = data;
461 	u16 flag;
462 
463 	if (!dev_priv) {
464 		DRM_ERROR("called with no initialization\n");
465 		return -EINVAL;
466 	}
467 
468 	flag = I915_READ(I915REG_INT_ENABLE_R);
469 	pipe->pipe = 0;
470 	if (flag & VSYNC_PIPEA_FLAG)
471 		pipe->pipe |= DRM_I915_VBLANK_PIPE_A;
472 	if (flag & VSYNC_PIPEB_FLAG)
473 		pipe->pipe |= DRM_I915_VBLANK_PIPE_B;
474 
475 	return 0;
476 }
477 
478 /**
479  * Schedule buffer swap at given vertical blank.
480  */
481 int i915_vblank_swap(struct drm_device *dev, void *data,
482 		     struct drm_file *file_priv)
483 {
484 	drm_i915_private_t *dev_priv = dev->dev_private;
485 	drm_i915_vblank_swap_t *swap = data;
486 	drm_i915_vbl_swap_t *vbl_swap;
487 	unsigned int pipe, seqtype, curseq;
488 	unsigned long irqflags;
489 	struct list_head *list;
490 
491 	if (!dev_priv) {
492 		DRM_ERROR("%s called with no initialization\n", __func__);
493 		return -EINVAL;
494 	}
495 
496 	if (dev_priv->sarea_priv->rotation) {
497 		DRM_DEBUG("Rotation not supported\n");
498 		return -EINVAL;
499 	}
500 
501 	if (swap->seqtype & ~(_DRM_VBLANK_RELATIVE | _DRM_VBLANK_ABSOLUTE |
502 			     _DRM_VBLANK_SECONDARY | _DRM_VBLANK_NEXTONMISS)) {
503 		DRM_ERROR("Invalid sequence type 0x%x\n", swap->seqtype);
504 		return -EINVAL;
505 	}
506 
507 	pipe = (swap->seqtype & _DRM_VBLANK_SECONDARY) ? 1 : 0;
508 
509 	seqtype = swap->seqtype & (_DRM_VBLANK_RELATIVE | _DRM_VBLANK_ABSOLUTE);
510 
511 	if (!(dev_priv->vblank_pipe & (1 << pipe))) {
512 		DRM_ERROR("Invalid pipe %d\n", pipe);
513 		return -EINVAL;
514 	}
515 
516 	spin_lock_irqsave(&dev->drw_lock, irqflags);
517 
518 	if (!drm_get_drawable_info(dev, swap->drawable)) {
519 		spin_unlock_irqrestore(&dev->drw_lock, irqflags);
520 		DRM_DEBUG("Invalid drawable ID %d\n", swap->drawable);
521 		return -EINVAL;
522 	}
523 
524 	spin_unlock_irqrestore(&dev->drw_lock, irqflags);
525 
526 	curseq = atomic_read(pipe ? &dev->vbl_received2 : &dev->vbl_received);
527 
528 	if (seqtype == _DRM_VBLANK_RELATIVE)
529 		swap->sequence += curseq;
530 
531 	if ((curseq - swap->sequence) <= (1<<23)) {
532 		if (swap->seqtype & _DRM_VBLANK_NEXTONMISS) {
533 			swap->sequence = curseq + 1;
534 		} else {
535 			DRM_DEBUG("Missed target sequence\n");
536 			return -EINVAL;
537 		}
538 	}
539 
540 	spin_lock_irqsave(&dev_priv->swaps_lock, irqflags);
541 
542 	list_for_each(list, &dev_priv->vbl_swaps.head) {
543 		vbl_swap = list_entry(list, drm_i915_vbl_swap_t, head);
544 
545 		if (vbl_swap->drw_id == swap->drawable &&
546 		    vbl_swap->pipe == pipe &&
547 		    vbl_swap->sequence == swap->sequence) {
548 			spin_unlock_irqrestore(&dev_priv->swaps_lock, irqflags);
549 			DRM_DEBUG("Already scheduled\n");
550 			return 0;
551 		}
552 	}
553 
554 	spin_unlock_irqrestore(&dev_priv->swaps_lock, irqflags);
555 
556 	if (dev_priv->swaps_pending >= 100) {
557 		DRM_DEBUG("Too many swaps queued\n");
558 		return -EBUSY;
559 	}
560 
561 	vbl_swap = drm_calloc(1, sizeof(*vbl_swap), DRM_MEM_DRIVER);
562 
563 	if (!vbl_swap) {
564 		DRM_ERROR("Failed to allocate memory to queue swap\n");
565 		return -ENOMEM;
566 	}
567 
568 	DRM_DEBUG("\n");
569 
570 	vbl_swap->drw_id = swap->drawable;
571 	vbl_swap->pipe = pipe;
572 	vbl_swap->sequence = swap->sequence;
573 
574 	spin_lock_irqsave(&dev_priv->swaps_lock, irqflags);
575 
576 	list_add_tail(&vbl_swap->head, &dev_priv->vbl_swaps.head);
577 	dev_priv->swaps_pending++;
578 
579 	spin_unlock_irqrestore(&dev_priv->swaps_lock, irqflags);
580 
581 	return 0;
582 }
583 
584 /* drm_dma.h hooks
585 */
586 void i915_driver_irq_preinstall(struct drm_device * dev)
587 {
588 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
589 
590 	I915_WRITE16(I915REG_HWSTAM, 0xfffe);
591 	I915_WRITE16(I915REG_INT_MASK_R, 0x0);
592 	I915_WRITE16(I915REG_INT_ENABLE_R, 0x0);
593 }
594 
595 void i915_driver_irq_postinstall(struct drm_device * dev)
596 {
597 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
598 
599 	spin_lock_init(&dev_priv->swaps_lock);
600 	INIT_LIST_HEAD(&dev_priv->vbl_swaps.head);
601 	dev_priv->swaps_pending = 0;
602 
603 	if (!dev_priv->vblank_pipe)
604 		dev_priv->vblank_pipe = DRM_I915_VBLANK_PIPE_A;
605 	i915_enable_interrupt(dev);
606 	DRM_INIT_WAITQUEUE(&dev_priv->irq_queue);
607 }
608 
609 void i915_driver_irq_uninstall(struct drm_device * dev)
610 {
611 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
612 	u16 temp;
613 
614 	if (!dev_priv)
615 		return;
616 
617 	I915_WRITE16(I915REG_HWSTAM, 0xffff);
618 	I915_WRITE16(I915REG_INT_MASK_R, 0xffff);
619 	I915_WRITE16(I915REG_INT_ENABLE_R, 0x0);
620 
621 	temp = I915_READ16(I915REG_INT_IDENTITY_R);
622 	I915_WRITE16(I915REG_INT_IDENTITY_R, temp);
623 }
624