--- title: Linux 7.4 Preps CXL For Very Neat Dynamic Capacity... description: Linux 7.4 merges the first preparatory code for CXL Dynamic Capacity Devices (DCD), memory expansion hardware that can scale server memory up or down without a... canonical: https://daily.dev/posts/linux-7-4-preps-cxl-for-very-neat-dynamic-capacity-devices-dcd--ulsxekkuo twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Linux 7.4 Preps CXL For Very Neat Dynamic Capacity Devices "DCD" | daily.dev og:description: Linux 7.4 merges the first preparatory code for CXL Dynamic Capacity Devices (DCD), memory expansion hardware that can scale server memory up or down without a... og:url: https://daily.dev/posts/linux-7-4-preps-cxl-for-very-neat-dynamic-capacity-devices-dcd--ulsxekkuo og:image: https://api.daily.dev/og/posts/ulsxEkKuo.png og:image:alt: Linux 7.4 Preps CXL For Very Neat Dynamic Capacity Devices "DCD" og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Linux 7.4 Preps CXL For Very Neat Dynamic Capacity Devices "DCD" **[Phoronix](https://daily.dev/sources/phoronix)** · 2 min read · 0 upvotes · 0 comments ## Summary Linux 7.4 merges the first preparatory code for CXL Dynamic Capacity Devices (DCD), memory expansion hardware that can scale server memory up or down without a reboot. The changes add mailbox flagging for DCD support, reading dynamic capacity configuration from devices, gathering DSMAS data for DCD partitions, and configuring dynamic capacity interrupts. DCD itself is not enabled yet; the patches were split up to ease review of a very large set. The pull also allows zero sized HDM decoders, adds switch decoder hardening, reworks GPF timeout programming, and makes latency calculations account for link width with consistent units. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What are CXL Dynamic Capacity Devices (DCD) and what do they do for server memory? CXL Dynamic Capacity Devices are Type-3 CXL memory expansion hardware that let server memory capacity scale up or down dynamically without rebooting or physically reconfiguring hardware. They allow reducing idle or over-provisioned memory by pooling resources across a rack through multi-host memory sharing, and bursting memory capacity on demand based on workload needs. _Teams planning CXL memory pooling can track kernel support progress for DCD on daily.dev._ ### Is CXL Dynamic Capacity Device support enabled in Linux 7.4? No, DCD is not enabled yet in Linux 7.4. The kernel merge for 7.4 only adds preparatory infrastructure: flagging DCD support in the mailbox, reading dynamic capacity configuration from the device, gathering DSMAS data for DCD partitions, and configuring dynamic capacity interrupts. The large patch set was split up to ease review burden, with remaining code still undergoing review. _Kernel engineers tracking CXL DCD enablement timelines can follow the rollout on daily.dev._ ## Similar posts on daily.dev - [Linux 6.20~7.0 To Bring Prep Changes For CXL Soft Reserve Recovery & Accelerator Memory](https://daily.dev/posts/linux-6-20-7-0-to-bring-prep-changes-for-cxl-soft-reserve-recovery-accelerator-memory-0rh5zfecv) · Phoronix · 0 upvotes · 0 comments - [Marvell Introduces Six-Channel CXL 3.2 Memory Expanders](https://daily.dev/posts/marvell-introduces-six-channel-cxl-3-2-memory-expanders-ttbrywpwv) · Embedded.com · 0 upvotes · 0 comments - [AMD Preps More Graphics Driver Improvements For Linux 7.3](https://daily.dev/posts/amd-preps-more-graphics-driver-improvements-for-linux-7-3-lpdj6ghad) · Phoronix · 0 upvotes · 0 comments - [Intel's Dynamic PAMT Appears Ready For Linux 7.4 To Help With TDX Memory Overhead](https://daily.dev/posts/intel-s-dynamic-pamt-appears-ready-for-linux-7-4-to-help-with-tdx-memory-overhead-tizuehqlk) · Phoronix · 0 upvotes · 0 comments --- Tags: [#linux](https://daily.dev/tags/linux) [View this post on daily.dev](https://daily.dev/posts/linux-7-4-preps-cxl-for-very-neat-dynamic-capacity-devices-dcd--ulsxekkuo) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Linux 7.4 Preps CXL For Very Neat Dynamic Capacity Devices \"DCD\"","url":"https://daily.dev/posts/linux-7-4-preps-cxl-for-very-neat-dynamic-capacity-devices-dcd--ulsxekkuo","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/linux-7-4-preps-cxl-for-very-neat-dynamic-capacity-devices-dcd--ulsxekkuo"},"datePublished":"2026-10-26T21:16:08.374Z","dateModified":"2026-10-26T21:49:03.123Z","description":"Linux 7.4 merges the first preparatory code for CXL Dynamic Capacity Devices (DCD), memory expansion hardware that can scale server memory up or down without a...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/3a40e3664d19666958491133cbba4146?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/3a40e3664d19666958491133cbba4146?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Phoronix","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Phoronix","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/6a26ba379dd64932830aa0c9803dd7ee","url":"https://daily.dev/sources/phoronix"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/linux-7-4-preps-cxl-for-very-neat-dynamic-capacity-devices-dcd--ulsxekkuo","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"linux","timeRequired":"PT2M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Phoronix","item":"https://daily.dev/sources/phoronix"},{"@type":"ListItem","position":3,"name":"Linux 7.4 Preps CXL For Very Neat Dynamic Capacity Devices \"DCD\""}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/linux-7-4-preps-cxl-for-very-neat-dynamic-capacity-devices-dcd--ulsxekkuo#faq","mainEntity":[{"@type":"Question","name":"What are CXL Dynamic Capacity Devices (DCD) and what do they do for server memory?","acceptedAnswer":{"@type":"Answer","text":"CXL Dynamic Capacity Devices are Type-3 CXL memory expansion hardware that let server memory capacity scale up or down dynamically without rebooting or physically reconfiguring hardware. 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