From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C86C838F64E for ; Mon, 7 Sep 2026 23:23:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788823424; cv=none; b=CJWOrF071W37r1zOTHEFR0wTxwl4eRnObu42GeCyi49nSXWigxXD9QKnDDcwiVaWrkvzvSfGxpAl0koIlwlf2pAXwiAHrYVB0ERFuLLUyTZ5rHEcyBTV30mLluaQqw+SWRl3U7I2ZPSRURq83zShCAxHLnhLQnG2DSZk0yQ/bHY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788823424; c=relaxed/simple; bh=Rr+onZVmPsSN8H/hLZZEfyXCyU8Ww/jdgvrGRBcxQAk=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=KVT+THB5ITXwjN88Q6Fb9OTrVSrmQR5nFlyKRPJSkq6J7rfJj45hVrcbJMOvzrxX7SKcwC+ww2MDN6N65gjJha1AlcqOZUaGoJe65mi4iaMYLduxXPjTTaVg/qy+PjxwgndQJH4mZwPnhRq/6wCRhuff/vL7+75C+2rVgTySM7E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mFLCwoD9; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mFLCwoD9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A99011F00A3A; Mon, 7 Sep 2026 23:23:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788823422; bh=Rn0DypIIKTyytamW7NiV1Oronfyrhfwri1tE3Bz7GBk=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=mFLCwoD9D6/OC87geIV7W0nVJwZRBhW+ClkIaCV4KZtbLoCn+3aaiSryoruKWlauv 1OXhXGIowKoSeVUImNSeLMb4aMigybLwqMg597BSHOK7p+ADUiBHt5Y1IGIrIJjICS bdMb3MEu2GJ+OaH4hd9KMQDmnBmdqi1orWVzztfyidDR/HwBuqwsa1ioyW0lEUz8sS RBgjH7CBvUImTCNlde1igT56Op3oq1jCnLViWUm/emg4On6zDGeCGUfGysel5FcuAs siPLOA1g9zfjcX2KQLQHCnyMAyMcwsb27/o1Em6nYv3dN+qHKzZyI3QVKs1rvV6h28 8INcNUFZiPyhA== Date: Tue, 8 Sep 2026 00:23:38 +0100 From: Jonathan Cameron To: Alison Schofield Cc: Davidlohr Bueso , Dave Jiang , Vishal Verma , Ira Weiny , Li Ming , Robert Richter , linux-cxl@vger.kernel.org Subject: Re: [PATCH v5 1/7] Documentation/cxl: Describe mixed-granularity regions Message-ID: <20260908002338.466c8ed3@jic23-huawei> In-Reply-To: <5da4008cde30c04284f5780aadac49e91ae511c1.1788475206.git.alison.schofield@intel.com> References: <5da4008cde30c04284f5780aadac49e91ae511c1.1788475206.git.alison.schofield@intel.com> X-Mailer: Claws Mail 4.4.0 (GTK 3.24.52; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 3 Sep 2026 16:23:43 -0700 Alison Schofield wrote: > Linux has required that a region's interleave granularity equal the > interleave granularity of its interleaving root decoder. A mixed- > granularity region lifts that restriction: the region granularity may be > finer than the root's, so the interleave refines from the root toward the > endpoints. > > Mixed-granularity region support introduces interleave relationships that > are not obvious from the existing CXL documentation. This is particularly > true for the 3-, 6-, and 12-way configurations and for understanding which > configurations permitted by the CXL Specification are supported by Linux. > > Document the mixed-granularity model and Linux's coarse-to-fine > restriction. Include the relevant configurations from CXL 4.0 Section > 9.13.1.1 and annotate their Linux support status. > > This intentionally repeats information from the CXL Specification. The > specification remains authoritative, but showing the Linux support policy > alongside the legal configurations ensures readers do not mistake an > unsupported Linux setup for a configuration unsupported by the CXL > Specification. > > Assisted-by: Claude:Opus-5 > Signed-off-by: Alison Schofield Reviewed-by: Jonathan Cameron