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path: root/drivers/gpu/drm/i915/i915_irq.c
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-rw-r--r--drivers/gpu/drm/i915/i915_irq.c623
1 files changed, 623 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
new file mode 100644
index 0000000..df03611
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -0,0 +1,623 @@
+/* i915_irq.c -- IRQ support for the I915 -*- linux-c -*-
+ */
+/*
+ * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
+ * 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 TUNGSTEN GRAPHICS 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.
+ *
+ */
+
+#include "drmP.h"
+#include "drm.h"
+#include "i915_drm.h"
+#include "i915_drv.h"
+
+#define USER_INT_FLAG (1<<1)
+#define VSYNC_PIPEB_FLAG (1<<5)
+#define VSYNC_PIPEA_FLAG (1<<7)
+
+#define MAX_NOPID ((u32)~0)
+
+/**
+ * Emit blits for scheduled buffer swaps.
+ *
+ * This function will be called with the HW lock held.
+ */
+static void i915_vblank_tasklet(struct drm_device *dev)
+{
+ drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+ unsigned long irqflags;
+ struct list_head *list, *tmp, hits, *hit;
+ int nhits, nrects, slice[2], upper[2], lower[2], i;
+ unsigned counter[2] = { atomic_read(&dev->vbl_received),
+ atomic_read(&dev->vbl_received2) };
+ struct drm_drawable_info *drw;
+ drm_i915_sarea_t *sarea_priv = dev_priv->sarea_priv;
+ u32 cpp = dev_priv->cpp;
+ u32 cmd = (cpp == 4) ? (XY_SRC_COPY_BLT_CMD |
+ XY_SRC_COPY_BLT_WRITE_ALPHA |
+ XY_SRC_COPY_BLT_WRITE_RGB)
+ : XY_SRC_COPY_BLT_CMD;
+ u32 src_pitch = sarea_priv->pitch * cpp;
+ u32 dst_pitch = sarea_priv->pitch * cpp;
+ u32 ropcpp = (0xcc << 16) | ((cpp - 1) << 24);
+ RING_LOCALS;
+
+ if (IS_I965G(dev) && sarea_priv->front_tiled) {
+ cmd |= XY_SRC_COPY_BLT_DST_TILED;
+ dst_pitch >>= 2;
+ }
+ if (IS_I965G(dev) && sarea_priv->back_tiled) {
+ cmd |= XY_SRC_COPY_BLT_SRC_TILED;
+ src_pitch >>= 2;
+ }
+
+ DRM_DEBUG("\n");
+
+ INIT_LIST_HEAD(&hits);
+
+ nhits = nrects = 0;
+
+ spin_lock_irqsave(&dev_priv->swaps_lock, irqflags);
+
+ /* Find buffer swaps scheduled for this vertical blank */
+ list_for_each_safe(list, tmp, &dev_priv->vbl_swaps.head) {
+ drm_i915_vbl_swap_t *vbl_swap =
+ list_entry(list, drm_i915_vbl_swap_t, head);
+
+ if ((counter[vbl_swap->pipe] - vbl_swap->sequence) > (1<<23))
+ continue;
+
+ list_del(list);
+ dev_priv->swaps_pending--;
+
+ spin_unlock(&dev_priv->swaps_lock);
+ spin_lock(&dev->drw_lock);
+
+ drw = drm_get_drawable_info(dev, vbl_swap->drw_id);
+
+ if (!drw) {
+ spin_unlock(&dev->drw_lock);
+ drm_free(vbl_swap, sizeof(*vbl_swap), DRM_MEM_DRIVER);
+ spin_lock(&dev_priv->swaps_lock);
+ continue;
+ }
+
+ list_for_each(hit, &hits) {
+ drm_i915_vbl_swap_t *swap_cmp =
+ list_entry(hit, drm_i915_vbl_swap_t, head);
+ struct drm_drawable_info *drw_cmp =
+ drm_get_drawable_info(dev, swap_cmp->drw_id);
+
+ if (drw_cmp &&
+ drw_cmp->rects[0].y1 > drw->rects[0].y1) {
+ list_add_tail(list, hit);
+ break;
+ }
+ }
+
+ spin_unlock(&dev->drw_lock);
+
+ /* List of hits was empty, or we reached the end of it */
+ if (hit == &hits)
+ list_add_tail(list, hits.prev);
+
+ nhits++;
+
+ spin_lock(&dev_priv->swaps_lock);
+ }
+
+ if (nhits == 0) {
+ spin_unlock_irqrestore(&dev_priv->swaps_lock, irqflags);
+ return;
+ }
+
+ spin_unlock(&dev_priv->swaps_lock);
+
+ i915_kernel_lost_context(dev);
+
+ if (IS_I965G(dev)) {
+ BEGIN_LP_RING(4);
+
+ OUT_RING(GFX_OP_DRAWRECT_INFO_I965);
+ OUT_RING(0);
+ OUT_RING(((sarea_priv->width - 1) & 0xffff) | ((sarea_priv->height - 1) << 16));
+ OUT_RING(0);
+ ADVANCE_LP_RING();
+ } else {
+ BEGIN_LP_RING(6);
+
+ OUT_RING(GFX_OP_DRAWRECT_INFO);
+ OUT_RING(0);
+ OUT_RING(0);
+ OUT_RING(sarea_priv->width | sarea_priv->height << 16);
+ OUT_RING(sarea_priv->width | sarea_priv->height << 16);
+ OUT_RING(0);
+
+ ADVANCE_LP_RING();
+ }
+
+ sarea_priv->ctxOwner = DRM_KERNEL_CONTEXT;
+
+ upper[0] = upper[1] = 0;
+ slice[0] = max(sarea_priv->pipeA_h / nhits, 1);
+ slice[1] = max(sarea_priv->pipeB_h / nhits, 1);
+ lower[0] = sarea_priv->pipeA_y + slice[0];
+ lower[1] = sarea_priv->pipeB_y + slice[0];
+
+ spin_lock(&dev->drw_lock);
+
+ /* Emit blits for buffer swaps, partitioning both outputs into as many
+ * slices as there are buffer swaps scheduled in order to avoid tearing
+ * (based on the assumption that a single buffer swap would always
+ * complete before scanout starts).
+ */
+ for (i = 0; i++ < nhits;
+ upper[0] = lower[0], lower[0] += slice[0],
+ upper[1] = lower[1], lower[1] += slice[1]) {
+ if (i == nhits)
+ lower[0] = lower[1] = sarea_priv->height;
+
+ list_for_each(hit, &hits) {
+ drm_i915_vbl_swap_t *swap_hit =
+ list_entry(hit, drm_i915_vbl_swap_t, head);
+ struct drm_clip_rect *rect;
+ int num_rects, pipe;
+ unsigned short top, bottom;
+
+ drw = drm_get_drawable_info(dev, swap_hit->drw_id);
+
+ if (!drw)
+ continue;
+
+ rect = drw->rects;
+ pipe = swap_hit->pipe;
+ top = upper[pipe];
+ bottom = lower[pipe];
+
+ for (num_rects = drw->num_rects; num_rects--; rect++) {
+ int y1 = max(rect->y1, top);
+ int y2 = min(rect->y2, bottom);
+
+ if (y1 >= y2)
+ continue;
+
+ BEGIN_LP_RING(8);
+
+ OUT_RING(cmd);
+ OUT_RING(ropcpp | dst_pitch);
+ OUT_RING((y1 << 16) | rect->x1);
+ OUT_RING((y2 << 16) | rect->x2);
+ OUT_RING(sarea_priv->front_offset);
+ OUT_RING((y1 << 16) | rect->x1);
+ OUT_RING(src_pitch);
+ OUT_RING(sarea_priv->back_offset);
+
+ ADVANCE_LP_RING();
+ }
+ }
+ }
+
+ spin_unlock_irqrestore(&dev->drw_lock, irqflags);
+
+ list_for_each_safe(hit, tmp, &hits) {
+ drm_i915_vbl_swap_t *swap_hit =
+ list_entry(hit, drm_i915_vbl_swap_t, head);
+
+ list_del(hit);
+
+ drm_free(swap_hit, sizeof(*swap_hit), DRM_MEM_DRIVER);
+ }
+}
+
+irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
+{
+ struct drm_device *dev = (struct drm_device *) arg;
+ drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+ u16 temp;
+ u32 pipea_stats, pipeb_stats;
+
+ pipea_stats = I915_READ(I915REG_PIPEASTAT);
+ pipeb_stats = I915_READ(I915REG_PIPEBSTAT);
+
+ temp = I915_READ16(I915REG_INT_IDENTITY_R);
+
+ temp &= (USER_INT_FLAG | VSYNC_PIPEA_FLAG | VSYNC_PIPEB_FLAG);
+
+ DRM_DEBUG("%s flag=%08x\n", __FUNCTION__, temp);
+
+ if (temp == 0)
+ return IRQ_NONE;
+
+ I915_WRITE16(I915REG_INT_IDENTITY_R, temp);
+ (void) I915_READ16(I915REG_INT_IDENTITY_R);
+ DRM_READMEMORYBARRIER();
+
+ dev_priv->sarea_priv->last_dispatch = READ_BREADCRUMB(dev_priv);
+
+ if (temp & USER_INT_FLAG)
+ DRM_WAKEUP(&dev_priv->irq_queue);
+
+ if (temp & (VSYNC_PIPEA_FLAG | VSYNC_PIPEB_FLAG)) {
+ int vblank_pipe = dev_priv->vblank_pipe;
+
+ if ((vblank_pipe &
+ (DRM_I915_VBLANK_PIPE_A | DRM_I915_VBLANK_PIPE_B))
+ == (DRM_I915_VBLANK_PIPE_A | DRM_I915_VBLANK_PIPE_B)) {
+ if (temp & VSYNC_PIPEA_FLAG)
+ atomic_inc(&dev->vbl_received);
+ if (temp & VSYNC_PIPEB_FLAG)
+ atomic_inc(&dev->vbl_received2);
+ } else if (((temp & VSYNC_PIPEA_FLAG) &&
+ (vblank_pipe & DRM_I915_VBLANK_PIPE_A)) ||
+ ((temp & VSYNC_PIPEB_FLAG) &&
+ (vblank_pipe & DRM_I915_VBLANK_PIPE_B)))
+ atomic_inc(&dev->vbl_received);
+
+ DRM_WAKEUP(&dev->vbl_queue);
+ drm_vbl_send_signals(dev);
+
+ if (dev_priv->swaps_pending > 0)
+ drm_locked_tasklet(dev, i915_vblank_tasklet);
+ I915_WRITE(I915REG_PIPEASTAT,
+ pipea_stats|I915_VBLANK_INTERRUPT_ENABLE|
+ I915_VBLANK_CLEAR);
+ I915_WRITE(I915REG_PIPEBSTAT,
+ pipeb_stats|I915_VBLANK_INTERRUPT_ENABLE|
+ I915_VBLANK_CLEAR);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int i915_emit_irq(struct drm_device * dev)
+{
+ drm_i915_private_t *dev_priv = dev->dev_private;
+ RING_LOCALS;
+
+ i915_kernel_lost_context(dev);
+
+ DRM_DEBUG("\n");
+
+ dev_priv->sarea_priv->last_enqueue = ++dev_priv->counter;
+
+ if (dev_priv->counter > 0x7FFFFFFFUL)
+ dev_priv->sarea_priv->last_enqueue = dev_priv->counter = 1;
+
+ BEGIN_LP_RING(6);
+ OUT_RING(CMD_STORE_DWORD_IDX);
+ OUT_RING(20);
+ OUT_RING(dev_priv->counter);
+ OUT_RING(0);
+ OUT_RING(0);
+ OUT_RING(GFX_OP_USER_INTERRUPT);
+ ADVANCE_LP_RING();
+
+ return dev_priv->counter;
+}
+
+static int i915_wait_irq(struct drm_device * dev, int irq_nr)
+{
+ drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+ int ret = 0;
+
+ DRM_DEBUG("irq_nr=%d breadcrumb=%d\n", irq_nr,
+ READ_BREADCRUMB(dev_priv));
+
+ if (READ_BREADCRUMB(dev_priv) >= irq_nr)
+ return 0;
+
+ dev_priv->sarea_priv->perf_boxes |= I915_BOX_WAIT;
+
+ DRM_WAIT_ON(ret, dev_priv->irq_queue, 3 * DRM_HZ,
+ READ_BREADCRUMB(dev_priv) >= irq_nr);
+
+ if (ret == -EBUSY) {
+ DRM_ERROR("EBUSY -- rec: %d emitted: %d\n",
+ READ_BREADCRUMB(dev_priv), (int)dev_priv->counter);
+ }
+
+ dev_priv->sarea_priv->last_dispatch = READ_BREADCRUMB(dev_priv);
+ return ret;
+}
+
+static int i915_driver_vblank_do_wait(struct drm_device *dev, unsigned int *sequence,
+ atomic_t *counter)
+{
+ drm_i915_private_t *dev_priv = dev->dev_private;
+ unsigned int cur_vblank;
+ int ret = 0;
+
+ if (!dev_priv) {
+ DRM_ERROR("called with no initialization\n");
+ return -EINVAL;
+ }
+
+ DRM_WAIT_ON(ret, dev->vbl_queue, 3 * DRM_HZ,
+ (((cur_vblank = atomic_read(counter))
+ - *sequence) <= (1<<23)));
+
+ *sequence = cur_vblank;
+
+ return ret;
+}
+
+
+int i915_driver_vblank_wait(struct drm_device *dev, unsigned int *sequence)
+{
+ return i915_driver_vblank_do_wait(dev, sequence, &dev->vbl_received);
+}
+
+int i915_driver_vblank_wait2(struct drm_device *dev, unsigned int *sequence)
+{
+ return i915_driver_vblank_do_wait(dev, sequence, &dev->vbl_received2);
+}
+
+/* Needs the lock as it touches the ring.
+ */
+int i915_irq_emit(struct drm_device *dev, void *data,
+ struct drm_file *file_priv)
+{
+ drm_i915_private_t *dev_priv = dev->dev_private;
+ drm_i915_irq_emit_t *emit = data;
+ int result;
+
+ LOCK_TEST_WITH_RETURN(dev, file_priv);
+
+ if (!dev_priv) {
+ DRM_ERROR("called with no initialization\n");
+ return -EINVAL;
+ }
+
+ result = i915_emit_irq(dev);
+
+ if (DRM_COPY_TO_USER(emit->irq_seq, &result, sizeof(int))) {
+ DRM_ERROR("copy_to_user\n");
+ return -EFAULT;
+ }
+
+ return 0;
+}
+
+/* Doesn't need the hardware lock.
+ */
+int i915_irq_wait(struct drm_device *dev, void *data,
+ struct drm_file *file_priv)
+{
+ drm_i915_private_t *dev_priv = dev->dev_private;
+ drm_i915_irq_wait_t *irqwait = data;
+
+ if (!dev_priv) {
+ DRM_ERROR("called with no initialization\n");
+ return -EINVAL;
+ }
+
+ return i915_wait_irq(dev, irqwait->irq_seq);
+}
+
+static void i915_enable_interrupt (struct drm_device *dev)
+{
+ drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+ u16 flag;
+
+ flag = 0;
+ if (dev_priv->vblank_pipe & DRM_I915_VBLANK_PIPE_A)
+ flag |= VSYNC_PIPEA_FLAG;
+ if (dev_priv->vblank_pipe & DRM_I915_VBLANK_PIPE_B)
+ flag |= VSYNC_PIPEB_FLAG;
+
+ I915_WRITE16(I915REG_INT_ENABLE_R, USER_INT_FLAG | flag);
+}
+
+/* Set the vblank monitor pipe
+ */
+int i915_vblank_pipe_set(struct drm_device *dev, void *data,
+ struct drm_file *file_priv)
+{
+ drm_i915_private_t *dev_priv = dev->dev_private;
+ drm_i915_vblank_pipe_t *pipe = data;
+
+ if (!dev_priv) {
+ DRM_ERROR("called with no initialization\n");
+ return -EINVAL;
+ }
+
+ if (pipe->pipe & ~(DRM_I915_VBLANK_PIPE_A|DRM_I915_VBLANK_PIPE_B)) {
+ DRM_ERROR("called with invalid pipe 0x%x\n", pipe->pipe);
+ return -EINVAL;
+ }
+
+ dev_priv->vblank_pipe = pipe->pipe;
+
+ i915_enable_interrupt (dev);
+
+ return 0;
+}
+
+int i915_vblank_pipe_get(struct drm_device *dev, void *data,
+ struct drm_file *file_priv)
+{
+ drm_i915_private_t *dev_priv = dev->dev_private;
+ drm_i915_vblank_pipe_t *pipe = data;
+ u16 flag;
+
+ if (!dev_priv) {
+ DRM_ERROR("called with no initialization\n");
+ return -EINVAL;
+ }
+
+ flag = I915_READ(I915REG_INT_ENABLE_R);
+ pipe->pipe = 0;
+ if (flag & VSYNC_PIPEA_FLAG)
+ pipe->pipe |= DRM_I915_VBLANK_PIPE_A;
+ if (flag & VSYNC_PIPEB_FLAG)
+ pipe->pipe |= DRM_I915_VBLANK_PIPE_B;
+
+ return 0;
+}
+
+/**
+ * Schedule buffer swap at given vertical blank.
+ */
+int i915_vblank_swap(struct drm_device *dev, void *data,
+ struct drm_file *file_priv)
+{
+ drm_i915_private_t *dev_priv = dev->dev_private;
+ drm_i915_vblank_swap_t *swap = data;
+ drm_i915_vbl_swap_t *vbl_swap;
+ unsigned int pipe, seqtype, curseq;
+ unsigned long irqflags;
+ struct list_head *list;
+
+ if (!dev_priv) {
+ DRM_ERROR("%s called with no initialization\n", __func__);
+ return -EINVAL;
+ }
+
+ if (dev_priv->sarea_priv->rotation) {
+ DRM_DEBUG("Rotation not supported\n");
+ return -EINVAL;
+ }
+
+ if (swap->seqtype & ~(_DRM_VBLANK_RELATIVE | _DRM_VBLANK_ABSOLUTE |
+ _DRM_VBLANK_SECONDARY | _DRM_VBLANK_NEXTONMISS)) {
+ DRM_ERROR("Invalid sequence type 0x%x\n", swap->seqtype);
+ return -EINVAL;
+ }
+
+ pipe = (swap->seqtype & _DRM_VBLANK_SECONDARY) ? 1 : 0;
+
+ seqtype = swap->seqtype & (_DRM_VBLANK_RELATIVE | _DRM_VBLANK_ABSOLUTE);
+
+ if (!(dev_priv->vblank_pipe & (1 << pipe))) {
+ DRM_ERROR("Invalid pipe %d\n", pipe);
+ return -EINVAL;
+ }
+
+ spin_lock_irqsave(&dev->drw_lock, irqflags);
+
+ if (!drm_get_drawable_info(dev, swap->drawable)) {
+ spin_unlock_irqrestore(&dev->drw_lock, irqflags);
+ DRM_DEBUG("Invalid drawable ID %d\n", swap->drawable);
+ return -EINVAL;
+ }
+
+ spin_unlock_irqrestore(&dev->drw_lock, irqflags);
+
+ curseq = atomic_read(pipe ? &dev->vbl_received2 : &dev->vbl_received);
+
+ if (seqtype == _DRM_VBLANK_RELATIVE)
+ swap->sequence += curseq;
+
+ if ((curseq - swap->sequence) <= (1<<23)) {
+ if (swap->seqtype & _DRM_VBLANK_NEXTONMISS) {
+ swap->sequence = curseq + 1;
+ } else {
+ DRM_DEBUG("Missed target sequence\n");
+ return -EINVAL;
+ }
+ }
+
+ spin_lock_irqsave(&dev_priv->swaps_lock, irqflags);
+
+ list_for_each(list, &dev_priv->vbl_swaps.head) {
+ vbl_swap = list_entry(list, drm_i915_vbl_swap_t, head);
+
+ if (vbl_swap->drw_id == swap->drawable &&
+ vbl_swap->pipe == pipe &&
+ vbl_swap->sequence == swap->sequence) {
+ spin_unlock_irqrestore(&dev_priv->swaps_lock, irqflags);
+ DRM_DEBUG("Already scheduled\n");
+ return 0;
+ }
+ }
+
+ spin_unlock_irqrestore(&dev_priv->swaps_lock, irqflags);
+
+ if (dev_priv->swaps_pending >= 100) {
+ DRM_DEBUG("Too many swaps queued\n");
+ return -EBUSY;
+ }
+
+ vbl_swap = drm_calloc(1, sizeof(*vbl_swap), DRM_MEM_DRIVER);
+
+ if (!vbl_swap) {
+ DRM_ERROR("Failed to allocate memory to queue swap\n");
+ return -ENOMEM;
+ }
+
+ DRM_DEBUG("\n");
+
+ vbl_swap->drw_id = swap->drawable;
+ vbl_swap->pipe = pipe;
+ vbl_swap->sequence = swap->sequence;
+
+ spin_lock_irqsave(&dev_priv->swaps_lock, irqflags);
+
+ list_add_tail(&vbl_swap->head, &dev_priv->vbl_swaps.head);
+ dev_priv->swaps_pending++;
+
+ spin_unlock_irqrestore(&dev_priv->swaps_lock, irqflags);
+
+ return 0;
+}
+
+/* drm_dma.h hooks
+*/
+void i915_driver_irq_preinstall(struct drm_device * dev)
+{
+ drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+
+ I915_WRITE16(I915REG_HWSTAM, 0xfffe);
+ I915_WRITE16(I915REG_INT_MASK_R, 0x0);
+ I915_WRITE16(I915REG_INT_ENABLE_R, 0x0);
+}
+
+void i915_driver_irq_postinstall(struct drm_device * dev)
+{
+ drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+
+ spin_lock_init(&dev_priv->swaps_lock);
+ INIT_LIST_HEAD(&dev_priv->vbl_swaps.head);
+ dev_priv->swaps_pending = 0;
+
+ if (!dev_priv->vblank_pipe)
+ dev_priv->vblank_pipe = DRM_I915_VBLANK_PIPE_A;
+ i915_enable_interrupt(dev);
+ DRM_INIT_WAITQUEUE(&dev_priv->irq_queue);
+}
+
+void i915_driver_irq_uninstall(struct drm_device * dev)
+{
+ drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
+ u16 temp;
+
+ if (!dev_priv)
+ return;
+
+ I915_WRITE16(I915REG_HWSTAM, 0xffff);
+ I915_WRITE16(I915REG_INT_MASK_R, 0xffff);
+ I915_WRITE16(I915REG_INT_ENABLE_R, 0x0);
+
+ temp = I915_READ16(I915REG_INT_IDENTITY_R);
+ I915_WRITE16(I915REG_INT_IDENTITY_R, temp);
+}
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