From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Mike Leach <mike.leach@linaro.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
Coresight ML <coresight@lists.linaro.org>,
"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
"Suzuki K. Poulose" <suzuki.poulose@arm.com>,
Jon Corbet <corbet@lwn.net>
Subject: Re: [PATCH v2 09/11] coresight: etm4x: docs: Update ABI doc for sysfs features added.
Date: Tue, 3 Sep 2019 16:51:40 -0600 [thread overview]
Message-ID: <CANLsYkwvasYKaepXuWdkTKDj7RquATaum-dmTZZQL237wesryQ@mail.gmail.com> (raw)
In-Reply-To: <20190903195951.GA25008@kroah.com>
On Tue, 3 Sep 2019 at 13:59, Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Thu, Aug 29, 2019 at 10:33:19PM +0100, Mike Leach wrote:
> > Update document to include the new sysfs features added during this
> > patchset.
> >
> > Updated to reflect the new sysfs component nameing schema.
> >
> > Signed-off-by: Mike Leach <mike.leach@linaro.org>
> > ---
> > .../testing/sysfs-bus-coresight-devices-etm4x | 183 +++++++++++-------
> > 1 file changed, 115 insertions(+), 68 deletions(-)
> >
> > diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
> > index 36258bc1b473..112c50ae9986 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
> > +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
> > @@ -1,4 +1,4 @@
> > -What: /sys/bus/coresight/devices/<memory_map>.etm/enable_source
> > +What: /sys/bus/coresight/devices/etm<N>/enable_source
>
> You are renaming sysfs directories that have been around since:
>
> > Date: April 2015
>
> ???
>
> Really?
>
> That's brave.
When I worked on the coresight sysfs ABI a while back I specifically
added it at the "testing" level as I was well aware that things could
change in the future. According to the guidelines in the
documentation userspace can rely on it which was accurate since the
interface didn't change for 4 years. But the guidelines also mention
that changes can occur before the interfaces are move to stables, and
that programs are encouraged to manifest their interest by adding
their name to the "users" field.
The interface was changed in 5.2 to support coresight from ACPI and
make things easier to understand for users. It is a lot more
intuitive to associate an ETM tracer with the CPU it belongs to by
referring to the CPU number than the memory mapped address. Given the
"testing" status of the interface and the absence of registered users
I decided to move forward with the change. If "testing" is too strict
for that I suggest to add an "experimental" category where it would be
more acceptable to change things as subsystems mature.
Thanks,
Mathieu
>
>
> What tool did you just break?
>
> greg k-h
next prev parent reply other threads:[~2019-09-03 22:51 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-29 21:33 [PATCH v2 00/11] coresight: etm4x: Fixes and updates for sysfs API Mike Leach
2019-08-29 21:33 ` [PATCH v2 01/11] coresight: etm4x: Fixes for ETM v4.4 architecture updates Mike Leach
2019-08-29 21:33 ` [PATCH v2 02/11] coresight: etm4x: Fix input validation for sysfs Mike Leach
2019-09-17 9:33 ` Suzuki K Poulose
2019-08-29 21:33 ` [PATCH v2 03/11] coresight: etm4x: Add missing API to set EL match on address filters Mike Leach
2019-09-17 9:31 ` Suzuki K Poulose
2019-10-26 20:26 ` [PATCH] coresight: etm4x: Fix BMVAL misuse Rikard Falkeborn
2019-10-30 15:19 ` Mathieu Poirier
2019-08-29 21:33 ` [PATCH v2 04/11] coresight: etm4x: Fix issues with start-stop logic Mike Leach
2019-08-29 21:33 ` [PATCH v2 05/11] coresight: etm4x: Improve usability of sysfs - include/exclude addr Mike Leach
2019-08-29 21:33 ` [PATCH v2 06/11] coresight: etm4x: Improve usability of sysfs - CID and VMID masks Mike Leach
2019-08-29 21:33 ` [PATCH v2 07/11] coresight: etm4x: Add view comparator settings API to sysfs Mike Leach
2019-08-29 21:33 ` [PATCH v2 08/11] coresight: etm4x: Add missing single-shot control " Mike Leach
2019-08-29 21:33 ` [PATCH v2 09/11] coresight: etm4x: docs: Update ABI doc for sysfs features added Mike Leach
2019-09-03 19:42 ` Mathieu Poirier
2019-09-03 19:59 ` Greg KH
2019-09-03 22:51 ` Mathieu Poirier [this message]
2019-09-04 5:48 ` Greg KH
2019-09-04 16:05 ` Mathieu Poirier
2019-09-04 16:17 ` Greg KH
2019-09-04 19:47 ` Mathieu Poirier
2019-08-29 21:33 ` [PATCH v2 10/11] coresight: docs: Create common sub-directory for coresight trace Mike Leach
2019-08-29 21:33 ` [PATCH v2 11/11] coresight: etm4x: docs: Adds detailed document for programming etm4x Mike Leach
2019-09-03 19:38 ` Mathieu Poirier
2019-09-03 22:46 ` Mike Leach
2019-09-04 16:09 ` Mathieu Poirier
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