ffmpeg | branch: master | Niklas Haas <g...@haasn.dev> | Fri Jun 20 14:21:51 2025 +0200| [27590d86534b0c94f12b9a206410f475fb008e72] | committer: Niklas Haas
avutil/hwcontext_vulkan: disable host transfers if ReBAR is disabled This feature fundamentally relies on host-visible VRAM, which restricts the set of available memory types to (typically) host-visible device-local ones. When resizable BAR is disabled, this memory type is usually limited to e.g. 256 MiB in size, which is just plain insufficient for allocation of general purpose GPU images, causing OOM errors on even the simplest of commands. The easiest solution is to disable host transfers entirely on machines without host-addressable VRAM. In theory, we could try and recover the use of host transfers for images which are *not* restricted to device-local memory types, but this is rarely the case in practice, and the effort required would exceed the benefit, especially since ReBAR is a standard feature on all platforms recent enough to have Vulkan drivers, and only occasionally disabled in the UEFI for by default for some hare-brained notion of "backwards compatibiility" with ancient software. > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=27590d86534b0c94f12b9a206410f475fb008e72 --- libavutil/hwcontext_vulkan.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/libavutil/hwcontext_vulkan.c b/libavutil/hwcontext_vulkan.c index edff89af26..b0a765e370 100644 --- a/libavutil/hwcontext_vulkan.c +++ b/libavutil/hwcontext_vulkan.c @@ -144,6 +144,9 @@ typedef struct VulkanDevicePriv { /* Disable multiplane images */ int disable_multiplane; + /* Disable host image transfer */ + int disable_host_transfer; + /* Maximum queues */ int limit_queues; @@ -1694,6 +1697,23 @@ static int vulkan_device_create_internal(AVHWDeviceContext *ctx, goto end; } + /* Get device memory properties */ + vk->GetPhysicalDeviceMemoryProperties(hwctx->phys_dev, &p->mprops); + VkDeviceSize max_vram = 0, max_visible_vram = 0; + for (int i = 0; i < p->mprops.memoryTypeCount; i++) { + const VkMemoryType type = p->mprops.memoryTypes[i]; + const VkMemoryHeap heap = p->mprops.memoryHeaps[type.heapIndex]; + if (!(type.propertyFlags & VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT)) + continue; + max_vram = FFMAX(max_vram, heap.size); + if (type.propertyFlags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT) + max_visible_vram = FFMAX(max_visible_vram, heap.size); + } + + /* Only use host image transfers if ReBAR is enabled */ + const int has_rebar = max_vram - max_visible_vram < 1024; /* 1 kB tolerance */ + p->disable_host_transfer = !has_rebar; + /* Get all supported features for the physical device */ device_features_init(ctx, &supported_feats); vk->GetPhysicalDeviceFeatures2(hwctx->phys_dev, &supported_feats.device); @@ -1990,9 +2010,6 @@ FF_ENABLE_DEPRECATION_WARNINGS if (!hwctx->unlock_queue) hwctx->unlock_queue = unlock_queue; - /* Get device capabilities */ - vk->GetPhysicalDeviceMemoryProperties(hwctx->phys_dev, &p->mprops); - p->vkctx.device = ctx; p->vkctx.hwctx = hwctx; @@ -2835,7 +2852,7 @@ static int vulkan_frames_init(AVHWFramesContext *hwfc) VK_IMAGE_USAGE_STORAGE_BIT | VK_IMAGE_USAGE_SAMPLED_BIT); - if (p->vkctx.extensions & FF_VK_EXT_HOST_IMAGE_COPY) + if ((p->vkctx.extensions & FF_VK_EXT_HOST_IMAGE_COPY) && !p->disable_host_transfer) hwctx->usage |= supported_usage & VK_IMAGE_USAGE_HOST_TRANSFER_BIT_EXT; /* Enables encoding of images, if supported by format and extensions */ _______________________________________________ ffmpeg-cvslog mailing list ffmpeg-cvslog@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog To unsubscribe, visit link above, or email ffmpeg-cvslog-requ...@ffmpeg.org with subject "unsubscribe".
