Date: Wed, 25 Feb 2009 18:22:57 +0000 (UTC) From: Robert Noland <rnoland@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r189047 - head/sys/dev/drm Message-ID: <200902251822.n1PIMvrI004406@svn.freebsd.org>
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Author: rnoland Date: Wed Feb 25 18:22:57 2009 New Revision: 189047 URL: http://svn.freebsd.org/changeset/base/189047 Log: The vblank_swap ioctl was fundamentally race prone. Get rid of it. MFC after: 2 weeks Modified: head/sys/dev/drm/i915_dma.c head/sys/dev/drm/i915_drv.h head/sys/dev/drm/i915_irq.c Modified: head/sys/dev/drm/i915_dma.c ============================================================================== --- head/sys/dev/drm/i915_dma.c Wed Feb 25 18:19:16 2009 (r189046) +++ head/sys/dev/drm/i915_dma.c Wed Feb 25 18:22:57 2009 (r189047) @@ -1087,7 +1087,6 @@ int i915_driver_load(struct drm_device * #ifdef I915_HAVE_GEM i915_gem_load(dev); #endif - DRM_SPININIT(&dev_priv->swaps_lock, "swap"); DRM_SPININIT(&dev_priv->user_irq_lock, "userirq"); #ifdef __linux__ @@ -1117,7 +1116,6 @@ int i915_driver_unload(struct drm_device drm_rmmap(dev, dev_priv->mmio_map); - DRM_SPINUNINIT(&dev_priv->swaps_lock); DRM_SPINUNINIT(&dev_priv->user_irq_lock); #ifdef __linux__ Modified: head/sys/dev/drm/i915_drv.h ============================================================================== --- head/sys/dev/drm/i915_drv.h Wed Feb 25 18:19:16 2009 (r189046) +++ head/sys/dev/drm/i915_drv.h Wed Feb 25 18:22:57 2009 (r189047) @@ -178,9 +178,6 @@ typedef struct drm_i915_private { struct drm_i915_validate_buffer *val_bufs; #endif - DRM_SPINTYPE swaps_lock; - drm_i915_vbl_swap_t vbl_swaps; - unsigned int swaps_pending; #if defined(I915_HAVE_BUFFER) /* DRI2 sarea */ struct drm_buffer_object *sarea_bo; Modified: head/sys/dev/drm/i915_irq.c ============================================================================== --- head/sys/dev/drm/i915_irq.c Wed Feb 25 18:19:16 2009 (r189046) +++ head/sys/dev/drm/i915_irq.c Wed Feb 25 18:22:57 2009 (r189047) @@ -121,277 +121,6 @@ i915_pipe_enabled(struct drm_device *dev return 0; } -/** - * Emit a synchronous flip. - * - * This function must be called with the drawable spinlock held. - */ -static void -i915_dispatch_vsync_flip(struct drm_device *dev, struct drm_drawable_info *drw, - int plane) -{ - drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private; - drm_i915_sarea_t *sarea_priv = dev_priv->sarea_priv; - u16 x1, y1, x2, y2; - int pf_planes = 1 << plane; - - DRM_SPINLOCK_ASSERT(&dev->drw_lock); - - /* If the window is visible on the other plane, we have to flip on that - * plane as well. - */ - if (plane == 1) { - x1 = sarea_priv->planeA_x; - y1 = sarea_priv->planeA_y; - x2 = x1 + sarea_priv->planeA_w; - y2 = y1 + sarea_priv->planeA_h; - } else { - x1 = sarea_priv->planeB_x; - y1 = sarea_priv->planeB_y; - x2 = x1 + sarea_priv->planeB_w; - y2 = y1 + sarea_priv->planeB_h; - } - - if (x2 > 0 && y2 > 0) { - int i, num_rects = drw->num_rects; - struct drm_clip_rect *rect = drw->rects; - - for (i = 0; i < num_rects; i++) - if (!(rect[i].x1 >= x2 || rect[i].y1 >= y2 || - rect[i].x2 <= x1 || rect[i].y2 <= y1)) { - pf_planes = 0x3; - - break; - } - } - - i915_dispatch_flip(dev, pf_planes, 1); -} - -/** - * 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; - struct list_head *list, *tmp, hits, *hit; - int nhits, nrects, slice[2], upper[2], lower[2], i, num_pages; - unsigned counter[2]; - struct drm_drawable_info *drw; - drm_i915_sarea_t *sarea_priv = dev_priv->sarea_priv; - u32 cpp = dev_priv->cpp, offsets[3]; - 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; - /* COPY rop (0xcc), map cpp to magic color depth constants */ - 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; - } - - counter[0] = drm_vblank_count(dev, 0); - counter[1] = drm_vblank_count(dev, 1); - - DRM_DEBUG("\n"); - - INIT_LIST_HEAD(&hits); - - nhits = nrects = 0; - - /* No irqsave/restore necessary. This tasklet may be run in an - * interrupt context or normal context, but we don't have to worry - * about getting interrupted by something acquiring the lock, because - * we are the interrupt context thing that acquires the lock. - */ - DRM_SPINLOCK(&dev_priv->swaps_lock); - - /* 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); - int pipe = i915_get_pipe(dev, vbl_swap->plane); - - if ((counter[pipe] - vbl_swap->sequence) > (1<<23)) - continue; - - list_del(list); - dev_priv->swaps_pending--; - drm_vblank_put(dev, pipe); - - DRM_SPINUNLOCK(&dev_priv->swaps_lock); - DRM_SPINLOCK(&dev->drw_lock); - - drw = drm_get_drawable_info(dev, vbl_swap->drw_id); - - if (!drw) { - DRM_SPINUNLOCK(&dev->drw_lock); - drm_free(vbl_swap, sizeof(*vbl_swap), DRM_MEM_DRIVER); - DRM_SPINLOCK(&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; - } - } - - DRM_SPINUNLOCK(&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++; - - DRM_SPINLOCK(&dev_priv->swaps_lock); - } - - DRM_SPINUNLOCK(&dev_priv->swaps_lock); - - if (nhits == 0) { - return; - } - - i915_kernel_lost_context(dev); - - upper[0] = upper[1] = 0; - slice[0] = max(sarea_priv->planeA_h / nhits, 1); - slice[1] = max(sarea_priv->planeB_h / nhits, 1); - lower[0] = sarea_priv->planeA_y + slice[0]; - lower[1] = sarea_priv->planeB_y + slice[0]; - - offsets[0] = sarea_priv->front_offset; - offsets[1] = sarea_priv->back_offset; - offsets[2] = sarea_priv->third_offset; - num_pages = sarea_priv->third_handle ? 3 : 2; - - DRM_SPINLOCK(&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]) { - int init_drawrect = 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, plane, front, back; - unsigned short top, bottom; - - drw = drm_get_drawable_info(dev, swap_hit->drw_id); - - if (!drw) - continue; - - plane = swap_hit->plane; - - if (swap_hit->flip) { - i915_dispatch_vsync_flip(dev, drw, plane); - continue; - } - - if (init_drawrect) { - int width = sarea_priv->width; - int height = sarea_priv->height; - if (IS_I965G(dev)) { - BEGIN_LP_RING(4); - - OUT_RING(GFX_OP_DRAWRECT_INFO_I965); - OUT_RING(0); - OUT_RING(((width - 1) & 0xffff) | ((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(((width - 1) & 0xffff) | ((height - 1) << 16)); - OUT_RING(0); - OUT_RING(0); - - ADVANCE_LP_RING(); - } - - sarea_priv->ctxOwner = DRM_KERNEL_CONTEXT; - - init_drawrect = 0; - } - - rect = drw->rects; - top = upper[plane]; - bottom = lower[plane]; - - front = (dev_priv->sarea_priv->pf_current_page >> - (2 * plane)) & 0x3; - back = (front + 1) % num_pages; - - 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(offsets[front]); - OUT_RING((y1 << 16) | rect->x1); - OUT_RING(src_pitch); - OUT_RING(offsets[back]); - - ADVANCE_LP_RING(); - } - } - } - - DRM_SPINUNLOCK(&dev->drw_lock); - - 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); - } -} - u32 i915_get_vblank_counter(struct drm_device *dev, int plane) { drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private; @@ -526,11 +255,6 @@ irqreturn_t i915_driver_irq_handler(DRM_ #endif } - if (vblank) { - if (dev_priv->swaps_pending > 0) - drm_locked_tasklet(dev, i915_vblank_tasklet); - } - return IRQ_HANDLED; } @@ -796,157 +520,22 @@ int i915_vblank_pipe_get(struct drm_devi 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, plane; - unsigned long irqflags; - struct list_head *list; - int ret; - - if (!dev_priv) { - DRM_ERROR("%s called with no initialization\n", __func__); - return -EINVAL; - } - - if (!dev_priv->sarea_priv || 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_VBLANK_FLIP)) { - DRM_ERROR("Invalid sequence type 0x%x\n", swap->seqtype); - return -EINVAL; - } - - plane = (swap->seqtype & _DRM_VBLANK_SECONDARY) ? 1 : 0; - pipe = i915_get_pipe(dev, plane); - - 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; - } - - DRM_SPINLOCK_IRQSAVE(&dev->drw_lock, irqflags); - - /* It makes no sense to schedule a swap for a drawable that doesn't have - * valid information at this point. E.g. this could mean that the X - * server is too old to push drawable information to the DRM, in which - * case all such swaps would become ineffective. + /* The delayed swap mechanism was fundamentally racy, and has been + * removed. The model was that the client requested a delayed flip/swap + * from the kernel, then waited for vblank before continuing to perform + * rendering. The problem was that the kernel might wake the client + * up before it dispatched the vblank swap (since the lock has to be + * held while touching the ringbuffer), in which case the client would + * clear and start the next frame before the swap occurred, and + * flicker would occur in addition to likely missing the vblank. + * + * In the absence of this ioctl, userland falls back to a correct path + * of waiting for a vblank, then dispatching the swap on its own. + * Context switching to userland and back is plenty fast enough for + * meeting the requirements of vblank swapping. */ - if (!drm_get_drawable_info(dev, swap->drawable)) { - DRM_SPINUNLOCK_IRQRESTORE(&dev->drw_lock, irqflags); - DRM_DEBUG("Invalid drawable ID %d\n", swap->drawable); - return -EINVAL; - } - - DRM_SPINUNLOCK_IRQRESTORE(&dev->drw_lock, irqflags); - - /* - * We take the ref here and put it when the swap actually completes - * in the tasklet. - */ - ret = drm_vblank_get(dev, pipe); - if (ret) - return ret; - curseq = drm_vblank_count(dev, pipe); - - 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"); - drm_vblank_put(dev, pipe); - return -EINVAL; - } - } - - if (swap->seqtype & _DRM_VBLANK_FLIP) { - swap->sequence--; - - if ((curseq - swap->sequence) <= (1<<23)) { - struct drm_drawable_info *drw; - - LOCK_TEST_WITH_RETURN(dev, file_priv); - DRM_SPINLOCK_IRQSAVE(&dev->drw_lock, irqflags); - - drw = drm_get_drawable_info(dev, swap->drawable); - - if (!drw) { - DRM_SPINUNLOCK_IRQRESTORE(&dev->drw_lock, - irqflags); - DRM_DEBUG("Invalid drawable ID %d\n", - swap->drawable); - drm_vblank_put(dev, pipe); - return -EINVAL; - } - - i915_dispatch_vsync_flip(dev, drw, plane); - - DRM_SPINUNLOCK_IRQRESTORE(&dev->drw_lock, irqflags); - - drm_vblank_put(dev, pipe); - return 0; - } - } - - DRM_SPINLOCK_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->plane == plane && - vbl_swap->sequence == swap->sequence) { - vbl_swap->flip = (swap->seqtype & _DRM_VBLANK_FLIP); - DRM_SPINUNLOCK_IRQRESTORE(&dev_priv->swaps_lock, irqflags); - DRM_DEBUG("Already scheduled\n"); - return 0; - } - } - - DRM_SPINUNLOCK_IRQRESTORE(&dev_priv->swaps_lock, irqflags); - - if (dev_priv->swaps_pending >= 100) { - DRM_DEBUG("Too many swaps queued\n"); - drm_vblank_put(dev, pipe); - 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"); - drm_vblank_put(dev, pipe); - return -ENOMEM; - } - - DRM_DEBUG("\n"); - - vbl_swap->drw_id = swap->drawable; - vbl_swap->plane = plane; - vbl_swap->sequence = swap->sequence; - vbl_swap->flip = (swap->seqtype & _DRM_VBLANK_FLIP); - - if (vbl_swap->flip) - swap->sequence++; - - DRM_SPINLOCK_IRQSAVE(&dev_priv->swaps_lock, irqflags); - - list_add_tail(&vbl_swap->head, &dev_priv->vbl_swaps.head); - dev_priv->swaps_pending++; - - DRM_SPINUNLOCK_IRQRESTORE(&dev_priv->swaps_lock, irqflags); - - return 0; + return -EINVAL; } /* drm_dma.h hooks @@ -965,9 +554,6 @@ int i915_driver_irq_postinstall(struct d drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private; int ret, num_pipes = 2; - INIT_LIST_HEAD(&dev_priv->vbl_swaps.head); - dev_priv->swaps_pending = 0; - dev_priv->user_irq_refcount = 0; dev_priv->irq_mask_reg = ~0;
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