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[173.79.56.208]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7c76e96cf01sm3584685a.55.2025.04.02.15.32.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Apr 2025 15:32:47 -0700 (PDT) Date: Wed, 2 Apr 2025 18:32:45 -0400 From: Gregory Price To: Dan Williams Cc: linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, vishal.l.verma@intel.com, dave.jiang@intel.com, dave@stgolabs.net, jonathan.cameron@huawei.com, alison.schofield@intel.com, ira.weiny@intel.com Subject: Re: [PATCH] cxl: core/region - ignore interleave granularity when ways=1 Message-ID: References: <20250402193443.944654-1-gourry@gourry.net> <67edb335dea8c_1a6d929437@dwillia2-xfh.jf.intel.com.notmuch> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <67edb335dea8c_1a6d929437@dwillia2-xfh.jf.intel.com.notmuch> On Wed, Apr 02, 2025 at 02:59:17PM -0700, Dan Williams wrote: > Gregory Price wrote: > > When validating decoder IW/IG when setting up regions, the granularity > > is irrelevant when iw=1 - all accesses will always route to the only > > target anyway - so all ig values are "correct". Loosen the requirement > > that `ig = (parent_iw * parent_ig)` when iw=1. > > Can you say a bit more here about the real world impact like we chatted > about on Discord? Something like: > > --- > The platform BIOS on "platform-X" specifies a 512-byte > interleave-granularity CXL Window when 256-byte is expected. This leads > to Linux erroneously rejecting the region configuration of 2 devices > attached to an x1 host bridge. > --- > > That way distros and platform-X folks can flag the importance of this fix. Would like this inline or just in the changelog? ~Gregory