LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Saravana Kannan <saravanak@google.com>
To: Sibi Sankar <sibis@codeaurora.org>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>,
	Kyungmin Park <kyungmin.park@samsung.com>,
	Chanwoo Choi <cw00.choi@samsung.com>,
	Viresh Kumar <vireshk@kernel.org>, Nishanth Menon <nm@ti.com>,
	Stephen Boyd <sboyd@kernel.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Android Kernel Team <kernel-team@android.com>,
	Linux PM <linux-pm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/4] OPP: Allow required-opps even if the device doesn't have power-domains
Date: Tue, 16 Jul 2019 11:54:50 -0700
Message-ID: <CAGETcx_LLj0Kd_1STijmPm+BbOK4UoY=qQ5Ruhjei3JCoOGhFw@mail.gmail.com> (raw)
In-Reply-To: <e7a5b387-fa85-15a8-8d79-fbc441c36293@codeaurora.org>

On Tue, Jul 16, 2019 at 10:18 AM Sibi Sankar <sibis@codeaurora.org> wrote:
>
> Hey Saravana,
> Thanks for taking time to post out this series.
>
> On 6/26/19 3:03 AM, Saravana Kannan wrote:
> > A Device-A can have a (minimum) performance requirement on another
> > Device-B to be able to function correctly. This performance requirement
> > on Device-B can also change based on the current performance level of
> > Device-A.
> >
> > The existing required-opps feature fits well to describe this need. So,
> > instead of limiting required-opps to point to only PM-domain devices,
> > allow it to point to any device.
> >
> > Signed-off-by: Saravana Kannan <saravanak@google.com>
> > ---
> >   drivers/opp/core.c |  2 +-
> >   drivers/opp/of.c   | 14 --------------
> >   2 files changed, 1 insertion(+), 15 deletions(-)
> >
> > diff --git a/drivers/opp/core.c b/drivers/opp/core.c
> > index 0e7703fe733f..74c7bdc6f463 100644
> > --- a/drivers/opp/core.c
> > +++ b/drivers/opp/core.c
> > @@ -710,7 +710,7 @@ static int _set_required_opps(struct device *dev,
> >               return 0;
> >
> >       /* Single genpd case */
> > -     if (!genpd_virt_devs) {
> > +     if (!genpd_virt_devs && required_opp_tables[0]->is_genpd) {
> https://patchwork.kernel.org/patch/10940671/
> This was already removed as a part of ^^ and is in linux-next.

Thanks for the heads up.

>
> >               pstate = opp->required_opps[0]->pstate;
> >               ret = dev_pm_genpd_set_performance_state(dev, pstate);
> >               if (ret) {
> > diff --git a/drivers/opp/of.c b/drivers/opp/of.c
> > index c10c782d15aa..7c8336e94aff 100644
> > --- a/drivers/opp/of.c
> > +++ b/drivers/opp/of.c
> > @@ -195,9 +195,6 @@ static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
> >        */
> >       count_pd = of_count_phandle_with_args(dev->of_node, "power-domains",
> >                                             "#power-domain-cells");
> > -     if (!count_pd)
> > -             goto put_np;
> > -
> >       if (count_pd > 1) {
> >               genpd_virt_devs = kcalloc(count, sizeof(*genpd_virt_devs),
> >                                       GFP_KERNEL);
> > @@ -226,17 +223,6 @@ static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
> >
> >               if (IS_ERR(required_opp_tables[i]))
> >                       goto free_required_tables;
> > -
> > -             /*
> > -              * We only support genpd's OPPs in the "required-opps" for now,
> > -              * as we don't know how much about other cases. Error out if the
> > -              * required OPP doesn't belong to a genpd.
> > -              */
> > -             if (!required_opp_tables[i]->is_genpd) {
> > -                     dev_err(dev, "required-opp doesn't belong to genpd: %pOF\n",
> > -                             required_np);
> > -                     goto free_required_tables;
> > -             }
>
> I expect the series to not work as is in its current state since I
> see a circular dependency here. The required-opp tables of the parent
> devfreq won't be populated until we add the opp-table of the child
> devfreq node while the child devfreq using passive governor would
> return -EPROBE_DEFER until the parent devfreq probes.

I looked into this when I wrote the patches. I thought I handled it
correctly. Let me take another look.

-Saravana

> The same applies to this patch -> https://patchwork.kernel.org/patch
> /11046147/ I posted out based on your series. So we would probably have
> to address the dependency here.
>
> >       }
> >
> >       goto put_np;
> >
>
> --
> Qualcomm Innovation Center, Inc.
> Qualcomm Innovation Center, Inc, is a member of Code Aurora Forum,
> a Linux Foundation Collaborative Project

  reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-25 21:33 [PATCH v2 0/4] Add required-opps support to devfreq passive gov Saravana Kannan
2019-06-25 21:33 ` [PATCH v2 1/4] OPP: Allow required-opps even if the device doesn't have power-domains Saravana Kannan
2019-07-16 15:14   ` Sibi Sankar
2019-07-16 17:17   ` Sibi Sankar
2019-07-16 18:54     ` Saravana Kannan [this message]
2019-06-25 21:33 ` [PATCH v2 2/4] OPP: Add function to look up required OPP's for a given OPP Saravana Kannan
2019-06-25 21:33 ` [PATCH v2 3/4] PM / devfreq: Cache OPP table reference in devfreq Saravana Kannan
2019-06-26  1:57   ` Chanwoo Choi
2019-07-16 17:36   ` Sibi Sankar
2019-07-16 19:12     ` Saravana Kannan
2019-06-25 21:33 ` [PATCH v2 4/4] PM / devfreq: Add required OPPs support to passive governor Saravana Kannan
2019-06-26  1:59   ` Chanwoo Choi
     [not found] ` <CGME20190625213355epcas5p3805e632818ee999a91e48ef9a610a084@epcms1p4>
2019-06-26  1:30   ` [PATCH v2 3/4] PM / devfreq: Cache OPP table reference in devfreq MyungJoo Ham
     [not found] ` <CGME20190625213358epcas4p2391bcf70b54646880cbb60eae8b73acf@epcms1p1>
2019-06-26  1:31   ` [PATCH v2 4/4] PM / devfreq: Add required OPPs support to passive governor MyungJoo Ham

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAGETcx_LLj0Kd_1STijmPm+BbOK4UoY=qQ5Ruhjei3JCoOGhFw@mail.gmail.com' \
    --to=saravanak@google.com \
    --cc=cw00.choi@samsung.com \
    --cc=kernel-team@android.com \
    --cc=kyungmin.park@samsung.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@vger.kernel.org \
    --cc=myungjoo.ham@samsung.com \
    --cc=nm@ti.com \
    --cc=rjw@rjwysocki.net \
    --cc=sboyd@kernel.org \
    --cc=sibis@codeaurora.org \
    --cc=vireshk@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org linux-kernel@archiver.kernel.org
	public-inbox-index lkml


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/ public-inbox