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From: fan <nifan.cxl@gmail.com>
Date: Tue, 26 Mar 2024 11:30:38 -0700
To: Davidlohr Bueso <dave@stgolabs.net>
Cc: ira.weiny@intel.com, Dave Jiang <dave.jiang@intel.com>,
	Fan Ni <fan.ni@samsung.com>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	Navneet Singh <navneet.singh@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Alison Schofield <alison.schofield@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>,
	linux-btrfs@vger.kernel.org, linux-cxl@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 08/26] cxl/mem: Expose device dynamic capacity
 capabilities
Message-ID: <ZgMUTq6HasHOiR15@debian>
References: <20240324-dcd-type2-upstream-v1-0-b7b00d623625@intel.com>
 <20240324-dcd-type2-upstream-v1-8-b7b00d623625@intel.com>
 <w4jkueqpvh7hzbywk42m7gxclg56nbgzhaqcgeb3q2b6dt3w6n@5vwicganqpsu>
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On Mon, Mar 25, 2024 at 04:40:16PM -0700, Davidlohr Bueso wrote:
> On Sun, 24 Mar 2024, ira.weiny@intel.com wrote:
> 
> > +What:		/sys/bus/cxl/devices/memX/dc/region_count
> > +Date:		June, 2024
> > +KernelVersion:	v6.10
> > +Contact:	linux-cxl@vger.kernel.org
> > +Description:
> > +		(RO) Number of Dynamic Capacity (DC) regions supported on the
> > +		device.  May be 0 if the device does not support Dynamic
> > +		Capacity.
> 
> If dcd is not supported then we should not have the dc/ directory
> altogether.
> 
> Thanks,
> Davidlohr 

I also think so. However, I also noticed one thing (not DCD related).
Even for a PMEM device, for example, we have a ram directory under the
device directory.

===================
root@DT:~# cxl list
[
  {
    "memdev":"mem0",
    "pmem_size":536870912,
    "serial":0,
    "host":"0000:0d:00.0"
  }
]
root@DT:~# ls /sys/bus/cxl/devices/mem0/
dc  dev  driver  firmware  firmware_version  label_storage_size  numa_node  payload_max  pmem  pmem0  ram  security  serial  subsystem	trigger_poison_list  uevent
root@DT:~#
===================

Fan