Re: [PATCH] cxl: core/region - ignore interleave granularity when ways=1

[Dan Williams]

Gregory Price wrote:
> 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?

Changelog is fine, because this more about routing the fix than
explaining the code.