Re: [PATCH 2/2]: acpica/nfit: Rename not-armed bit definition

[Dan Williams]

On Wed, Aug 26, 2015 at 2:44 PM, Toshi Kani <toshi.kani@xxxxxx> wrote:
> On Wed, 2015-08-26 at 14:30 -0700, Dan Williams wrote:
>> On Wed, Aug 26, 2015 at 2:12 PM, Toshi Kani <toshi.kani@xxxxxx> wrote:
>> > On Wed, 2015-08-26 at 10:16 -0700, Dan Williams wrote:
>> > > On Wed, Aug 26, 2015 at 9:20 AM, Toshi Kani <toshi.kani@xxxxxx> wrote:
>> > > > ACPI 6.0 NFIT Memory Device State Flags in Table 5-129 defines
>> > > > bit 3 as follows.
>> > > >
>> > > >   Bit [3] set to 1 to indicate that the Memory Device is observed
>> > > >   to be not armed prior to OSPM hand off. A Memory Device is
>> > > >   considered armed if it is able to accept persistent writes.
>> > > >
>> > > > This bit is currently defined as ACPI_NFIT_MEM_ARMED, which can be
>> > > > confusing as if the Memory Device is armed when this bit is set.
>> > > >
>> > > > Change the name to ACPI_NFIT_MEM_NOT_ARMED per the spec.
>> > > >
>> > > > Signed-off-by: Toshi Kani <toshi.kani@xxxxxx>
>> > > > Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
>> > > > Cc: Bob Moore <robert.moore@xxxxxxxxx>
>> > > > Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>> > > > ---
>> > > >  drivers/acpi/nfit.c              |    6 +++---
>> > > >  drivers/acpi/nfit.h              |    2 +-
>> > > >  include/acpi/actbl1.h            |    2 +-
>> > >
>> > > This file "include/acpi/actbl1.h" is owned by the ACPICA project so
>> > > any changes need to come through them.  But that said, I'm not sure we
>> > > need friendly names at this level.
>> >
>> > I think the name is misleading, but I agree with the process and this
>> > patch2
>> > can be dropped.  It'd be nice if the ACPICA project can pick it up later
>> > when they have a chance, though.
>> >
>> > > What I usually say about sysfs name changes to be more human friendly
>> > > is "sysfs is not a UI", i.e. it's not necessarily meant to be user
>> > > friendly.  As long as the names for the flags are distinct then
>> > > wrapping descriptive / accurate names around them is the role of
>> > > libndctl and userspace management software.
>> > >
>> > > Similar feedback for patch1 in the sense that I don't think we need to
>> > > update the sysfs naming.  For example the API to retrieve the state of
>> > > the "arm" flag in libndctl is ndctl_dimm_failed_arm().
>> >
>> > I agree that we do not want to change sysfs API for friendliness, and I
>> > understand that libndctl already consumes the strings...  But I think
>> > they
>> > can be confusing for the long run, i.e. the flags is likely extended for
>> > additional info, and more people may be looking at sysfs for the state.
>> >  It'd be a lot harder to change them later.
>>
>> The starting premise though is that this will be nicer for scripts
>> that want to avoid the library.  Properly handling the async device
>> registration semantics of the libnvdimm-sysfs interface is hard to get
>> right in a script.  I'm trying my best to discourage raw use of sysfs
>> for this reason.  Small fixes to the names of flags seems to miss this
>> wider point.
>
> Okay, I guess I will have to jump on the bandwagon and discourage people to
> look at sysfs... ;-P
>

That said, I'm not opposed to looking at something like Python-binding
for libndctl to make scripting easier.
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