Re: [PATCH v4 2/4] cxl/hdm: Only interpret interleave settings on committed decoders

[Alison Schofield <alison.schofield@intel.com>]

On Wed, Jul 29, 2026 at 09:34:35AM -0700, Davidlohr Bueso wrote:
> On Mon, 20 Jul 2026, Alison Schofield wrote:
> 
> > Decoder enumeration reads the interleave ways and granularity fields
> > from the CTRL register unconditionally, then decodes and validates
> > them for every decoder. On an uncommitted decoder these fields are
> > stale. They hold whatever was last latched and are reprogrammed when
> > the decoder is committed. Interpreting them serves no purpose, and
> > rejecting enumeration on a reserved encoding in those stale bits can
> > fail an otherwise usable decoder.
> > 
> > Decode and validate interleave ways and granularity only when the
> > decoder is committed. On an uncommitted decoder the stale register
> > values are not interpreted. The interleave fields are set when the
> > decoder is programmed at commit time.
> > 
> 
> It's weird to cat the respective sysfs file and get bogus values.
> imo this should be kept as is.

Thanks for the reviews Davidlohr,

Agreed, the patch is dropped in v5. It changes what userspace sees:
decoderX.Y/interleave_ways and decoderX.Y/interleave_granularity are
documented read-only attributes that report the decoded register fields,
and skipping the decode makes them report driver defaults instead.


> 
> Thanks,
> Davidlohr