From: Ulf Hansson <ulf.hansson@linaro.org>
To: Stephen Boyd <swboyd@chromium.org>, Mark Rutland <mark.rutland@arm.com>
Cc: "Rafael J . Wysocki" <rjw@rjwysocki.net>,
Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
Sudeep Holla <sudeep.holla@arm.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Lina Iyer <ilina@codeaurora.org>,
Linux PM <linux-pm@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 7/7] drivers: firmware: psci: Announce support for OS initiated suspend mode
Date: Mon, 4 Mar 2019 11:25:43 +0100 [thread overview]
Message-ID: <CAPDyKFodEYc+9UoROhH-wWYYZPBnMTu1ZhkCM9gSHDrYTq=MFA@mail.gmail.com> (raw)
In-Reply-To: <155146129938.16805.4528027710288083607@swboyd.mtv.corp.google.com>
On Fri, 1 Mar 2019 at 18:28, Stephen Boyd <swboyd@chromium.org> wrote:
>
> Quoting Ulf Hansson (2019-02-28 05:59:19)
> > PSCI firmware v1.0+, supports two different modes for CPU_SUSPEND. The
> > Platform Coordinated mode, which is the default and mandatory mode, while
> > support for the OS initiated (OSI) mode is optional.
> >
> > In some cases it's interesting for the user/developer to know if the OSI
> > mode is supported by the PSCI FW. Therefore, let's print a message to the
> > log, if that is the case.
>
> I don't see anything wrong with the patch besides the potential for the
> logs to wrap and the informational message to be lost, but would it be
> possible to express the PSCI features that are supported in sysfs at
> /sys/firmware/psci/ somehow? It may be useful for a user to know that
> their firmware has PSCI support and that it has a certain set of
> features available, like OSI vs. PC, or both. I don't know of any use
> that userspace would have though, besides maybe the CPU state residency
> counters being used by some sort of statistics collecting program or
> just plain knowing that certain PSCI features are present, so perhaps it
> could just be done in debugfs for now until a real user exists.
Having a sysfs interface for PSCI, allowing users to know a little bit
more about what the FW supports/version/etc sound like a great idea to
me.
There is already quite some prints being made by psci during boot, so
perhaps having sysfs allows us to drop some of these.
Mark, what do you think? Is it something you think we should do? I can
offer my help to implement this, if you think it's a good idea.
Stephen, thanks for reviewing!
Kind regards
Uffe
next prev parent reply other threads:[~2019-03-04 10:26 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-28 13:59 [PATCH 0/7] drivers: firmware: psci: Some cleanup and refactoring Ulf Hansson
2019-02-28 13:59 ` [PATCH 1/7] drivers: firmware: psci: Move psci to separate directory Ulf Hansson
2019-02-28 14:34 ` Daniel Lezcano
2019-03-01 17:03 ` Mark Rutland
2019-02-28 13:59 ` [PATCH 2/7] MAINTAINERS: Update files for PSCI Ulf Hansson
2019-02-28 14:35 ` Daniel Lezcano
2019-03-01 17:04 ` Mark Rutland
2019-02-28 13:59 ` [PATCH 3/7] drivers: firmware: psci: Split psci_dt_cpu_init_idle() Ulf Hansson
2019-02-28 14:42 ` Daniel Lezcano
2019-02-28 22:13 ` Ulf Hansson
2019-03-01 17:07 ` Mark Rutland
2019-02-28 13:59 ` [PATCH 4/7] ARM/ARM64: cpuidle: Let back-end init ops take the driver as input Ulf Hansson
2019-02-28 15:30 ` Daniel Lezcano
2019-03-01 17:31 ` Mark Rutland
2019-02-28 13:59 ` [PATCH 5/7] drivers: firmware: psci: Simplify state node parsing Ulf Hansson
2019-02-28 15:40 ` Daniel Lezcano
2019-02-28 22:26 ` Ulf Hansson
2019-02-28 22:41 ` Daniel Lezcano
2019-03-01 17:28 ` Mark Rutland
2019-03-04 10:14 ` Ulf Hansson
2019-03-06 18:15 ` Lorenzo Pieralisi
2019-03-08 10:36 ` Ulf Hansson
2019-03-08 11:49 ` Lorenzo Pieralisi
2019-03-08 13:07 ` Ulf Hansson
2019-03-08 13:17 ` Lorenzo Pieralisi
2019-03-08 13:23 ` Ulf Hansson
2019-03-08 13:31 ` Lorenzo Pieralisi
2019-03-08 13:43 ` Ulf Hansson
2019-02-28 13:59 ` [PATCH 6/7] drivers: firmware: psci: Simplify error path of psci_dt_init() Ulf Hansson
2019-02-28 13:59 ` [PATCH 7/7] drivers: firmware: psci: Announce support for OS initiated suspend mode Ulf Hansson
2019-03-01 17:28 ` Stephen Boyd
2019-03-04 10:25 ` Ulf Hansson [this message]
2019-03-01 17:32 ` Mark Rutland
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