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Date:   Tue, 2 Nov 2021 09:58:01 -0700
From:   Ben Widawsky <ben.widawsky@intel.com>
To:     Dan Williams <dan.j.williams@intel.com>
Cc:     linux-cxl@vger.kernel.org, Chet Douglas <chet.r.douglas@intel.com>,
        Alison Schofield <alison.schofield@intel.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Vishal Verma <vishal.l.verma@intel.com>
Subject: Re: [RFC PATCH v2 08/28] cxl/port: Introduce a port driver
Message-ID: <20211102165801.6mxobbz3ow55nkzl@intel.com>
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On 21-11-01 20:31:03, Dan Williams wrote:
> On Mon, Nov 1, 2021 at 10:53 AM Ben Widawsky <ben.widawsky@intel.com> wrote:
> >
> > On 21-10-29 18:37:36, Dan Williams wrote:
> > > On Fri, Oct 22, 2021 at 11:37 AM Ben Widawsky <ben.widawsky@intel.com> wrote:
> > > >
> >
> > [snip]
> >
> > > > diff --git a/drivers/cxl/Makefile b/drivers/cxl/Makefile
> > > > index cf07ae6cea17..40b386aaedf7 100644
> > > > --- a/drivers/cxl/Makefile
> > > > +++ b/drivers/cxl/Makefile
> > > > @@ -1,5 +1,6 @@
> > > >  # SPDX-License-Identifier: GPL-2.0
> > > >  obj-$(CONFIG_CXL_BUS) += core/
> > > > +obj-$(CONFIG_CXL_MEM) += cxl_port.o
> > >
> > > It feel odd that CONFIG_CXL_MEM builds cxl_port, why not have a
> > > CONFIG_CXL_PORT that is simply selected by CONFIG_CXL_MEM, or a
> > > CONFIG_CXL_PORT that defaults to the value of CONFIG_CXL_BUS?
> > >
> >
> > Can you help me understand when CONFIG_CXL_MEM is useful when
> > #CONFIG_CXL_PORT=n? I was unable to figure out such a case and so I tied the two
> > together.
> 
> With a 'select' dependency it's impossible to have the
> CONFIG_CXL_PORT=n and CONFIG_CXL_MEM=m combination. The extra config
> symbol is for idiomatic (one config-symbol per module .ko) reasons to
> reflect the module dependency in the Kconfig.
> 

Should CXL_MEM also select CXL_PCI? I don't see a way CXL_MEM can work without
CXL_PCI.

[snip]