From patchwork Fri Aug 30 14:47:17 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lionel Landwerlin X-Patchwork-Id: 11124199 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9B0E718B7 for ; Fri, 30 Aug 2019 14:47:43 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 81F1623426 for ; Fri, 30 Aug 2019 14:47:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 81F1623426 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D65106E353; Fri, 30 Aug 2019 14:47:42 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by gabe.freedesktop.org (Postfix) with ESMTPS id CD4636E357 for ; Fri, 30 Aug 2019 14:47:35 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 30 Aug 2019 07:47:35 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,447,1559545200"; d="scan'208";a="188894197" Received: from unknown (HELO delly.ger.corp.intel.com) ([10.252.38.85]) by FMSMGA003.fm.intel.com with ESMTP; 30 Aug 2019 07:47:34 -0700 From: Lionel Landwerlin To: intel-gfx@lists.freedesktop.org Date: Fri, 30 Aug 2019 17:47:17 +0300 Message-Id: <20190830144726.18291-3-lionel.g.landwerlin@intel.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190830144726.18291-1-lionel.g.landwerlin@intel.com> References: <20190830144726.18291-1-lionel.g.landwerlin@intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH v12 02/11] drm/i915: add syncobj timeline support X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Introduces a new parameters to execbuf so that we can specify syncobj handles as well as timeline points. v2: Reuse i915_user_extension_fn v3: Check that the chained extension is only present once (Chris) v4: Check that dma_fence_chain_find_seqno returns a non NULL fence (Lionel) v5: Use BIT_ULL (Chris) v6: Fix issue with already signaled timeline points, dma_fence_chain_find_seqno() setting fence to NULL (Chris) v7: Report ENOENT with invalid syncobj handle (Lionel) v8: Check for out of order timeline point insertion (Chris) v9: After explanations on https://lists.freedesktop.org/archives/dri-devel/2019-August/229287.html drop the ordering check from v8 (Lionel) v10: Set first extension enum item to 1 (Jason) Signed-off-by: Lionel Landwerlin --- .../gpu/drm/i915/gem/i915_gem_execbuffer.c | 307 ++++++++++++++---- drivers/gpu/drm/i915/i915_drv.c | 3 +- drivers/gpu/drm/i915/i915_getparam.c | 1 + include/uapi/drm/i915_drm.h | 39 +++ 4 files changed, 293 insertions(+), 57 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c index 4f5fd946ab28..46ad8d9642d1 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c @@ -214,6 +214,13 @@ enum { * the batchbuffer in trusted mode, otherwise the ioctl is rejected. */ +struct i915_eb_fences { + struct drm_syncobj *syncobj; /* Use with ptr_mask_bits() */ + struct dma_fence *dma_fence; + u64 value; + struct dma_fence_chain *chain_fence; +}; + struct i915_execbuffer { struct drm_i915_private *i915; /** i915 backpointer */ struct drm_file *file; /** per-file lookup tables and limits */ @@ -276,6 +283,7 @@ struct i915_execbuffer { struct { u64 flags; /** Available extensions parameters */ + struct drm_i915_gem_execbuffer_ext_timeline_fences timeline_fences; } extensions; }; @@ -2320,67 +2328,217 @@ eb_pin_engine(struct i915_execbuffer *eb, } static void -__free_fence_array(struct drm_syncobj **fences, unsigned int n) +__free_fence_array(struct i915_eb_fences *fences, unsigned int n) { - while (n--) - drm_syncobj_put(ptr_mask_bits(fences[n], 2)); + while (n--) { + drm_syncobj_put(ptr_mask_bits(fences[n].syncobj, 2)); + dma_fence_put(fences[n].dma_fence); + kfree(fences[n].chain_fence); + } kvfree(fences); } -static struct drm_syncobj ** -get_fence_array(struct drm_i915_gem_execbuffer2 *args, - struct drm_file *file) +static struct i915_eb_fences * +get_timeline_fence_array(struct i915_execbuffer *eb, int *out_n_fences) +{ + struct drm_i915_gem_execbuffer_ext_timeline_fences *timeline_fences = + &eb->extensions.timeline_fences; + struct drm_i915_gem_exec_fence __user *user_fences; + struct i915_eb_fences *fences; + u64 __user *user_values; + u64 num_fences, num_user_fences = timeline_fences->fence_count; + unsigned long n; + int err; + + /* Check multiplication overflow for access_ok() and kvmalloc_array() */ + BUILD_BUG_ON(sizeof(size_t) > sizeof(unsigned long)); + if (num_user_fences > min_t(unsigned long, + ULONG_MAX / sizeof(*user_fences), + SIZE_MAX / sizeof(*fences))) + return ERR_PTR(-EINVAL); + + user_fences = u64_to_user_ptr(timeline_fences->handles_ptr); + if (!access_ok(user_fences, num_user_fences * sizeof(*user_fences))) + return ERR_PTR(-EFAULT); + + user_values = u64_to_user_ptr(timeline_fences->values_ptr); + if (!access_ok(user_values, num_user_fences * sizeof(*user_values))) + return ERR_PTR(-EFAULT); + + fences = kvmalloc_array(num_user_fences, sizeof(*fences), + __GFP_NOWARN | GFP_KERNEL); + if (!fences) + return ERR_PTR(-ENOMEM); + + BUILD_BUG_ON(~(ARCH_KMALLOC_MINALIGN - 1) & + ~__I915_EXEC_FENCE_UNKNOWN_FLAGS); + + for (n = 0, num_fences = 0; n < timeline_fences->fence_count; n++) { + struct drm_i915_gem_exec_fence user_fence; + struct drm_syncobj *syncobj; + struct dma_fence *fence = NULL; + u64 point; + + if (__copy_from_user(&user_fence, user_fences++, sizeof(user_fence))) { + err = -EFAULT; + goto err; + } + + if (user_fence.flags & __I915_EXEC_FENCE_UNKNOWN_FLAGS) { + err = -EINVAL; + goto err; + } + + if (__get_user(point, user_values++)) { + err = -EFAULT; + goto err; + } + + syncobj = drm_syncobj_find(eb->file, user_fence.handle); + if (!syncobj) { + DRM_DEBUG("Invalid syncobj handle provided\n"); + err = -ENOENT; + goto err; + } + + if (user_fence.flags & I915_EXEC_FENCE_WAIT) { + fence = drm_syncobj_fence_get(syncobj); + if (!fence) { + DRM_DEBUG("Syncobj handle has no fence\n"); + drm_syncobj_put(syncobj); + err = -EINVAL; + goto err; + } + + err = dma_fence_chain_find_seqno(&fence, point); + if (err) { + DRM_DEBUG("Syncobj handle missing requested point %llu\n", point); + drm_syncobj_put(syncobj); + goto err; + } + + /* A point might have been signaled already and + * garbage collected from the timeline. In this case + * just ignore the point and carry on. + */ + if (!fence) { + drm_syncobj_put(syncobj); + continue; + } + } + + /* + * For timeline syncobjs we need to preallocate chains for + * later signaling. + */ + if (point != 0 && user_fence.flags & I915_EXEC_FENCE_SIGNAL) { + /* + * Waiting and signaling the same point (when point != + * 0) would break the timeline. + */ + if (user_fence.flags & I915_EXEC_FENCE_WAIT) { + DRM_DEBUG("Tring to wait & signal the same timeline point.\n"); + err = -EINVAL; + drm_syncobj_put(syncobj); + goto err; + } + + fences[num_fences].chain_fence = + kmalloc(sizeof(*fences[num_fences].chain_fence), + GFP_KERNEL); + if (!fences[num_fences].chain_fence) { + drm_syncobj_put(syncobj); + err = -ENOMEM; + DRM_DEBUG("Unable to alloc chain_fence\n"); + goto err; + } + } else { + fences[num_fences].chain_fence = NULL; + } + + fences[num_fences].syncobj = ptr_pack_bits(syncobj, user_fence.flags, 2); + fences[num_fences].dma_fence = fence; + fences[num_fences].value = point; + num_fences++; + } + + *out_n_fences = num_fences; + + return fences; + +err: + __free_fence_array(fences, num_fences); + return ERR_PTR(err); +} + +static struct i915_eb_fences * +get_legacy_fence_array(struct i915_execbuffer *eb, + int *out_n_fences) { - const unsigned long nfences = args->num_cliprects; + struct drm_i915_gem_execbuffer2 *args = eb->args; struct drm_i915_gem_exec_fence __user *user; - struct drm_syncobj **fences; + struct i915_eb_fences *fences; + const u32 num_fences = args->num_cliprects; unsigned long n; int err; - if (!(args->flags & I915_EXEC_FENCE_ARRAY)) - return NULL; + *out_n_fences = num_fences; /* Check multiplication overflow for access_ok() and kvmalloc_array() */ BUILD_BUG_ON(sizeof(size_t) > sizeof(unsigned long)); - if (nfences > min_t(unsigned long, - ULONG_MAX / sizeof(*user), - SIZE_MAX / sizeof(*fences))) + if (*out_n_fences > min_t(unsigned long, + ULONG_MAX / sizeof(*user), + SIZE_MAX / sizeof(*fences))) return ERR_PTR(-EINVAL); user = u64_to_user_ptr(args->cliprects_ptr); - if (!access_ok(user, nfences * sizeof(*user))) + if (!access_ok(user, *out_n_fences * sizeof(*user))) return ERR_PTR(-EFAULT); - fences = kvmalloc_array(nfences, sizeof(*fences), + fences = kvmalloc_array(*out_n_fences, sizeof(*fences), __GFP_NOWARN | GFP_KERNEL); if (!fences) return ERR_PTR(-ENOMEM); - for (n = 0; n < nfences; n++) { - struct drm_i915_gem_exec_fence fence; + for (n = 0; n < *out_n_fences; n++) { + struct drm_i915_gem_exec_fence user_fence; struct drm_syncobj *syncobj; + struct dma_fence *fence = NULL; - if (__copy_from_user(&fence, user++, sizeof(fence))) { + if (__copy_from_user(&user_fence, user++, sizeof(user_fence))) { err = -EFAULT; goto err; } - if (fence.flags & __I915_EXEC_FENCE_UNKNOWN_FLAGS) { + if (user_fence.flags & __I915_EXEC_FENCE_UNKNOWN_FLAGS) { err = -EINVAL; goto err; } - syncobj = drm_syncobj_find(file, fence.handle); + syncobj = drm_syncobj_find(eb->file, user_fence.handle); if (!syncobj) { DRM_DEBUG("Invalid syncobj handle provided\n"); err = -ENOENT; goto err; } + if (user_fence.flags & I915_EXEC_FENCE_WAIT) { + fence = drm_syncobj_fence_get(syncobj); + if (!fence) { + DRM_DEBUG("Syncobj handle has no fence\n"); + drm_syncobj_put(syncobj); + err = -EINVAL; + goto err; + } + } + BUILD_BUG_ON(~(ARCH_KMALLOC_MINALIGN - 1) & ~__I915_EXEC_FENCE_UNKNOWN_FLAGS); - fences[n] = ptr_pack_bits(syncobj, fence.flags, 2); + fences[n].syncobj = ptr_pack_bits(syncobj, user_fence.flags, 2); + fences[n].dma_fence = fence; + fences[n].value = 0; + fences[n].chain_fence = NULL; } return fences; @@ -2390,37 +2548,44 @@ get_fence_array(struct drm_i915_gem_execbuffer2 *args, return ERR_PTR(err); } +static struct i915_eb_fences * +get_fence_array(struct i915_execbuffer *eb, int *out_n_fences) +{ + if (eb->args->flags & I915_EXEC_FENCE_ARRAY) + return get_legacy_fence_array(eb, out_n_fences); + + if (eb->extensions.flags & BIT_ULL(DRM_I915_GEM_EXECBUFFER_EXT_TIMELINE_FENCES)) + return get_timeline_fence_array(eb, out_n_fences); + + *out_n_fences = 0; + return NULL; +} + static void -put_fence_array(struct drm_i915_gem_execbuffer2 *args, - struct drm_syncobj **fences) +put_fence_array(struct i915_eb_fences *fences, int nfences) { if (fences) - __free_fence_array(fences, args->num_cliprects); + __free_fence_array(fences, nfences); } static int await_fence_array(struct i915_execbuffer *eb, - struct drm_syncobj **fences) + struct i915_eb_fences *fences, + int nfences) { - const unsigned int nfences = eb->args->num_cliprects; unsigned int n; int err; for (n = 0; n < nfences; n++) { struct drm_syncobj *syncobj; - struct dma_fence *fence; unsigned int flags; - syncobj = ptr_unpack_bits(fences[n], &flags, 2); + syncobj = ptr_unpack_bits(fences[n].syncobj, &flags, 2); if (!(flags & I915_EXEC_FENCE_WAIT)) continue; - fence = drm_syncobj_fence_get(syncobj); - if (!fence) - return -EINVAL; - - err = i915_request_await_dma_fence(eb->request, fence); - dma_fence_put(fence); + err = i915_request_await_dma_fence(eb->request, + fences[n].dma_fence); if (err < 0) return err; } @@ -2430,9 +2595,9 @@ await_fence_array(struct i915_execbuffer *eb, static void signal_fence_array(struct i915_execbuffer *eb, - struct drm_syncobj **fences) + struct i915_eb_fences *fences, + int nfences) { - const unsigned int nfences = eb->args->num_cliprects; struct dma_fence * const fence = &eb->request->fence; unsigned int n; @@ -2440,15 +2605,46 @@ signal_fence_array(struct i915_execbuffer *eb, struct drm_syncobj *syncobj; unsigned int flags; - syncobj = ptr_unpack_bits(fences[n], &flags, 2); + syncobj = ptr_unpack_bits(fences[n].syncobj, &flags, 2); if (!(flags & I915_EXEC_FENCE_SIGNAL)) continue; - drm_syncobj_replace_fence(syncobj, fence); + if (fences[n].chain_fence) { + drm_syncobj_add_point(syncobj, fences[n].chain_fence, + fence, fences[n].value); + /* + * The chain's ownership is transfered to the + * timeline. + */ + fences[n].chain_fence = NULL; + } else { + drm_syncobj_replace_fence(syncobj, fence); + } } } +static int parse_timeline_fences(struct i915_user_extension __user *ext, void *data) +{ + struct i915_execbuffer *eb = data; + + /* Timeline fences are incompatible with the fence array flag. */ + if (eb->args->flags & I915_EXEC_FENCE_ARRAY) + return -EINVAL; + + if (eb->extensions.flags & BIT_ULL(DRM_I915_GEM_EXECBUFFER_EXT_TIMELINE_FENCES)) + return -EINVAL; + + if (copy_from_user(&eb->extensions.timeline_fences, ext, + sizeof(eb->extensions.timeline_fences))) + return -EFAULT; + + eb->extensions.flags |= BIT_ULL(DRM_I915_GEM_EXECBUFFER_EXT_TIMELINE_FENCES); + + return 0; +} + static const i915_user_extension_fn execbuf_extensions[] = { + [DRM_I915_GEM_EXECBUFFER_EXT_TIMELINE_FENCES] = parse_timeline_fences, }; static int @@ -2479,14 +2675,15 @@ static int i915_gem_do_execbuffer(struct drm_device *dev, struct drm_file *file, struct drm_i915_gem_execbuffer2 *args, - struct drm_i915_gem_exec_object2 *exec, - struct drm_syncobj **fences) + struct drm_i915_gem_exec_object2 *exec) { struct i915_execbuffer eb; struct dma_fence *in_fence = NULL; struct dma_fence *exec_fence = NULL; struct sync_file *out_fence = NULL; + struct i915_eb_fences *fences = NULL; int out_fence_fd = -1; + int nfences = 0; int err; BUILD_BUG_ON(__EXEC_INTERNAL_FLAGS & ~__I915_EXEC_ILLEGAL_FLAGS); @@ -2525,10 +2722,16 @@ i915_gem_do_execbuffer(struct drm_device *dev, if (err) return err; + fences = get_fence_array(&eb, &nfences); + if (IS_ERR(fences)) + return PTR_ERR(fences); + if (args->flags & I915_EXEC_FENCE_IN) { in_fence = sync_file_get_fence(lower_32_bits(args->rsvd2)); - if (!in_fence) - return -EINVAL; + if (!in_fence) { + err = -EINVAL; + goto err_fences; + } } if (args->flags & I915_EXEC_FENCE_SUBMIT) { @@ -2673,7 +2876,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, } if (fences) { - err = await_fence_array(&eb, fences); + err = await_fence_array(&eb, fences, nfences); if (err) goto err_request; } @@ -2704,7 +2907,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, i915_request_add(eb.request); if (fences) - signal_fence_array(&eb, fences); + signal_fence_array(&eb, fences, nfences); if (out_fence) { if (err == 0) { @@ -2739,6 +2942,8 @@ i915_gem_do_execbuffer(struct drm_device *dev, dma_fence_put(exec_fence); err_in_fence: dma_fence_put(in_fence); +err_fences: + put_fence_array(fences, nfences); return err; } @@ -2832,7 +3037,7 @@ i915_gem_execbuffer_ioctl(struct drm_device *dev, void *data, exec2_list[i].flags = 0; } - err = i915_gem_do_execbuffer(dev, file, &exec2, exec2_list, NULL); + err = i915_gem_do_execbuffer(dev, file, &exec2, exec2_list); if (exec2.flags & __EXEC_HAS_RELOC) { struct drm_i915_gem_exec_object __user *user_exec_list = u64_to_user_ptr(args->buffers_ptr); @@ -2863,7 +3068,6 @@ i915_gem_execbuffer2_ioctl(struct drm_device *dev, void *data, { struct drm_i915_gem_execbuffer2 *args = data; struct drm_i915_gem_exec_object2 *exec2_list; - struct drm_syncobj **fences = NULL; const size_t count = args->buffer_count; int err; @@ -2891,15 +3095,7 @@ i915_gem_execbuffer2_ioctl(struct drm_device *dev, void *data, return -EFAULT; } - if (args->flags & I915_EXEC_FENCE_ARRAY) { - fences = get_fence_array(args, file); - if (IS_ERR(fences)) { - kvfree(exec2_list); - return PTR_ERR(fences); - } - } - - err = i915_gem_do_execbuffer(dev, file, args, exec2_list, fences); + err = i915_gem_do_execbuffer(dev, file, args, exec2_list); /* * Now that we have begun execution of the batchbuffer, we ignore @@ -2939,7 +3135,6 @@ end:; } args->flags &= ~__I915_EXEC_UNKNOWN_FLAGS; - put_fence_array(args, fences); kvfree(exec2_list); return err; } diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index bec25942d77d..4e21858fe110 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -2820,7 +2820,8 @@ static struct drm_driver driver = { */ .driver_features = DRIVER_GEM | - DRIVER_RENDER | DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_SYNCOBJ, + DRIVER_RENDER | DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_SYNCOBJ | + DRIVER_SYNCOBJ_TIMELINE, .release = i915_driver_release, .open = i915_driver_open, .lastclose = i915_driver_lastclose, diff --git a/drivers/gpu/drm/i915/i915_getparam.c b/drivers/gpu/drm/i915/i915_getparam.c index 5d9101376a3d..da6faa84e5b8 100644 --- a/drivers/gpu/drm/i915/i915_getparam.c +++ b/drivers/gpu/drm/i915/i915_getparam.c @@ -130,6 +130,7 @@ int i915_getparam_ioctl(struct drm_device *dev, void *data, case I915_PARAM_HAS_EXEC_BATCH_FIRST: case I915_PARAM_HAS_EXEC_FENCE_ARRAY: case I915_PARAM_HAS_EXEC_SUBMIT_FENCE: + case I915_PARAM_HAS_EXEC_TIMELINE_FENCES: /* For the time being all of these are always true; * if some supported hardware does not have one of these * features this value needs to be provided from diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index 0a99c26730e1..3d031e81648b 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -611,6 +611,13 @@ typedef struct drm_i915_irq_wait { * See I915_EXEC_FENCE_OUT and I915_EXEC_FENCE_SUBMIT. */ #define I915_PARAM_HAS_EXEC_SUBMIT_FENCE 53 + +/* Query whether DRM_I915_GEM_EXECBUFFER2 supports supplying an array of + * timeline syncobj through drm_i915_gem_execbuf_ext_timeline_fences. See + * I915_EXEC_USE_EXTENSIONS. + */ +#define I915_PARAM_HAS_EXEC_TIMELINE_FENCES 54 + /* Must be kept compact -- no holes and well documented */ typedef struct drm_i915_getparam { @@ -1008,9 +1015,41 @@ struct drm_i915_gem_exec_fence { }; enum drm_i915_gem_execbuffer_ext { + /** + * See drm_i915_gem_execbuf_ext_timeline_fences. + */ + DRM_I915_GEM_EXECBUFFER_EXT_TIMELINE_FENCES = 1, + DRM_I915_GEM_EXECBUFFER_EXT_MAX /* non-ABI */ }; +/** + * This structure describes an array of drm_syncobj and associated points for + * timeline variants of drm_syncobj. It is invalid to append this structure to + * the execbuf if I915_EXEC_FENCE_ARRAY is set. + */ +struct drm_i915_gem_execbuffer_ext_timeline_fences { + struct i915_user_extension base; + + /** + * Number of element in the handles_ptr & value_ptr arrays. + */ + __u64 fence_count; + + /** + * Pointer to an array of struct drm_i915_gem_exec_fence of length + * fence_count. + */ + __u64 handles_ptr; + + /** + * Pointer to an array of u64 values of length fence_count. Values + * must be 0 for a binary drm_syncobj. A Value of 0 for a timeline + * drm_syncobj is invalid as it turns a drm_syncobj into a binary one. + */ + __u64 values_ptr; +}; + struct drm_i915_gem_execbuffer2 { /** * List of gem_exec_object2 structs