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From: Viresh Kumar <viresh.kumar@linaro.org>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: "Thierry Reding" <thierry.reding@gmail.com>,
	"Jonathan Hunter" <jonathanh@nvidia.com>,
	"Ulf Hansson" <ulf.hansson@linaro.org>,
	"Viresh Kumar" <vireshk@kernel.org>,
	"Stephen Boyd" <sboyd@kernel.org>,
	"Peter De Schrijver" <pdeschrijver@nvidia.com>,
	"Mikko Perttunen" <mperttunen@nvidia.com>,
	"Peter Chen" <peter.chen@kernel.org>,
	"Mark Brown" <broonie@kernel.org>,
	"Lee Jones" <lee.jones@linaro.org>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Nishanth Menon" <nm@ti.com>,
	"Vignesh Raghavendra" <vigneshr@ti.com>,
	"Richard Weinberger" <richard@nod.at>,
	"Miquel Raynal" <miquel.raynal@bootlin.com>,
	"Lucas Stach" <dev@lynxeye.de>, "Stefan Agner" <stefan@agner.ch>,
	"Adrian Hunter" <adrian.hunter@intel.com>,
	"Mauro Carvalho Chehab" <mchehab@kernel.org>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Michael Turquette" <mturquette@baylibre.com>,
	linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org,
	linux-pm@vger.kernel.org, linux-usb@vger.kernel.org,
	linux-staging@lists.linux.dev, linux-spi@vger.kernel.org,
	linux-pwm@vger.kernel.org, linux-mtd@lists.infradead.org,
	linux-mmc@vger.kernel.org, linux-media@vger.kernel.org,
	dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
	linux-clk@vger.kernel.org
Subject: Re: [PATCH v8 01/34] opp: Add dev_pm_opp_sync() helper
Date: Wed, 18 Aug 2021 11:28:49 +0530	[thread overview]
Message-ID: <20210818055849.ybfajzu75ecpdrbn@vireshk-i7> (raw)
In-Reply-To: <080469b3-612b-3a34-86e5-7037a64de2fe@gmail.com>

On 18-08-21, 08:21, Dmitry Osipenko wrote:
> Yes, GENPD will cache the perf state across suspend/resume and initially
> cached value is out of sync with h/w.
> 
> Nothing else. But let me clarify it all again.

Thanks for your explanation.

> Initially the performance state of all GENPDs is 0 for all devices.
> 
> The clock rate is preinitialized for all devices to a some default rate
> by clk driver, or by bootloader or by assigned-clocks in DT.
> 
> When device is rpm-resumed, the resume callback of a device driver
> enables the clock.
> 
> Before clock is enabled, the voltage needs to be configured in
> accordance to the clk rate.
> 
> So now we have a GENPD with pstate=0 on a first rpm-resume, which
> doesn't match the h/w configuration. Calling dev_pm_opp_sync() sets the
> pstate in accordance to the h/w config.

What about calling dev_pm_opp_set_rate(dev, clk_get_rate(dev)) here
instead ? That will work, right ? The advantage is it works without
any special routine to do so.

I also wonder looking at your gr3d.c changes, you set a set-opp
helper, but the driver doesn't call set_opp_rate at all. Who calls it
?

And if it is all about just syncing the genpd core, then can the genpd
core do something like what clk framework does? i.e. allow a new
optional genpd callback, get_performance_state() (just like
set_performance_state()), which can be called initially by the core to
get the performance to something other than zero. opp-set-rate is
there to set the performance state and enable the stuff as well.
That's why it looks incorrect in your case, where the function was
only required to be called once, and you are ending up calling it on
each resume. Limiting that with another local variable is bad as well.

> In a previous v7 I proposed to preset the rpm_pstate of GENPD (perf
> level that is restored before device is rpm-resumed) from PD's
> attach_dev callback, but Ulf didn't like that because it requires to use
> and modify GENPD 'private' variables from a PD driver. We decided that
> will be better to make device drivers to explicitly sync the perf state,
> which I implemented in this v8.

-- 
viresh

  reply	other threads:[~2021-08-18  5:58 UTC|newest]

Thread overview: 119+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-17  1:27 [PATCH v8 00/34] NVIDIA Tegra power management patches for 5.16 Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 01/34] opp: Add dev_pm_opp_sync() helper Dmitry Osipenko
2021-08-17  7:55   ` Viresh Kumar
2021-08-17 15:49     ` Dmitry Osipenko
2021-08-18  3:55       ` Viresh Kumar
2021-08-18  4:12         ` Dmitry Osipenko
2021-08-18  4:29           ` Dmitry Osipenko
2021-08-18  4:30             ` Dmitry Osipenko
2021-08-18  4:34               ` Viresh Kumar
2021-08-18  4:31           ` Viresh Kumar
2021-08-18  4:37             ` Dmitry Osipenko
2021-08-18  4:53               ` Viresh Kumar
2021-08-18  5:21                 ` Dmitry Osipenko
2021-08-18  5:58                   ` Viresh Kumar [this message]
2021-08-18  6:00                     ` Viresh Kumar
2021-08-18  6:22                     ` Dmitry Osipenko
2021-08-18  6:27                       ` Viresh Kumar
2021-08-18  8:29                         ` Ulf Hansson
2021-08-18  9:14                           ` Viresh Kumar
2021-08-18  9:41                             ` Ulf Hansson
2021-08-18  9:42                               ` Ulf Hansson
2021-08-18  9:50                               ` Viresh Kumar
2021-08-18 10:08                                 ` Ulf Hansson
2021-08-18 15:43                                   ` Dmitry Osipenko
2021-08-18 15:46                                     ` Dmitry Osipenko
2021-08-19 13:07                                     ` Ulf Hansson
2021-08-19 19:35                                       ` Dmitry Osipenko
2021-08-20  5:07                                         ` Viresh Kumar
2021-08-20 12:42                                         ` Ulf Hansson
2021-08-21 17:34                                           ` Dmitry Osipenko
2021-08-23 10:46                                             ` Ulf Hansson
2021-08-23 15:54                                               ` Dmitry Osipenko
2021-08-18 15:55                               ` Dmitry Osipenko
2021-08-19  6:16                                 ` Viresh Kumar
2021-08-19 14:55                                   ` Ulf Hansson
2021-08-20  5:18                                     ` Viresh Kumar
2021-08-20 12:57                                       ` Ulf Hansson
2021-08-23 20:24                                         ` Dmitry Osipenko
2021-08-24  3:04                                           ` Viresh Kumar
2021-08-22 18:35                                       ` Dmitry Osipenko
2021-08-25 15:41                                         ` Dmitry Osipenko
2021-08-26  2:54                                           ` Viresh Kumar
2021-08-26  2:55                                             ` Viresh Kumar
2021-08-17  1:27 ` [PATCH v8 02/34] soc/tegra: pmc: Disable PMC state syncing Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 03/34] soc/tegra: Don't print error message when OPPs not available Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 04/34] soc/tegra: Add devm_tegra_core_dev_init_opp_table_simple() Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 05/34] soc/tegra: Use dev_pm_opp_sync() Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 06/34] dt-bindings: clock: tegra-car: Document new tegra-clocks sub-node Dmitry Osipenko
2021-08-18  1:15   ` Rob Herring
2021-08-18  1:44     ` Dmitry Osipenko
2021-08-18 13:52       ` Thierry Reding
2021-08-18 15:04         ` Dmitry Osipenko
2021-08-18 13:59   ` Thierry Reding
2021-08-18 15:05     ` Dmitry Osipenko
2021-08-18 16:39       ` Thierry Reding
2021-08-18 16:57         ` Dmitry Osipenko
2021-08-18 17:16           ` Dmitry Osipenko
2021-08-19 16:31           ` Thierry Reding
2021-08-19 22:20             ` Dmitry Osipenko
2021-08-20  2:51             ` Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 07/34] clk: tegra: Support runtime PM and power domain Dmitry Osipenko
2021-08-18 14:07   ` Thierry Reding
2021-08-18 15:05     ` Dmitry Osipenko
2021-08-18 16:42       ` Thierry Reding
2021-08-18 17:11         ` Dmitry Osipenko
2021-08-19 16:54           ` Thierry Reding
2021-08-19 22:09             ` Dmitry Osipenko
2021-08-20 11:42               ` Thierry Reding
2021-08-20 13:08                 ` Ulf Hansson
2021-08-21 17:45                   ` Dmitry Osipenko
2021-08-23 14:33                     ` Thierry Reding
2021-08-23 18:54                       ` Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 08/34] dt-bindings: host1x: Document OPP and power domain properties Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 09/34] dt-bindings: host1x: Document Memory Client resets of Host1x, GR2D and GR3D Dmitry Osipenko
2021-08-18  1:16   ` Rob Herring
2021-08-18  1:37     ` Dmitry Osipenko
2021-08-18  2:04       ` Dmitry Osipenko
2021-08-18  2:07         ` Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 10/34] gpu: host1x: Add host1x_channel_stop() Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 11/34] gpu: host1x: Add runtime PM and OPP support Dmitry Osipenko
2021-08-17 12:04   ` Ulf Hansson
2021-08-17 14:02     ` Thierry Reding
2021-08-18  8:35       ` Ulf Hansson
2021-08-18 17:24         ` Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 12/34] drm/tegra: dc: Support OPP and SoC core voltage scaling Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 13/34] drm/tegra: hdmi: Add OPP support Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 14/34] drm/tegra: gr2d: Support power management Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 15/34] drm/tegra: gr3d: " Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 16/34] drm/tegra: vic: Support system suspend Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 17/34] usb: chipidea: tegra: Add runtime PM and OPP support Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 18/34] bus: tegra-gmi: " Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 19/34] pwm: tegra: " Dmitry Osipenko
2021-08-19 13:21   ` Thierry Reding
2021-08-19 14:04     ` Ulf Hansson
2021-08-19 16:17       ` Thierry Reding
2021-08-17  1:27 ` [PATCH v8 20/34] mmc: sdhci-tegra: " Dmitry Osipenko
2021-08-19 17:03   ` Thierry Reding
2021-08-19 22:37     ` Dmitry Osipenko
2021-08-20 11:35       ` Thierry Reding
2021-08-25  9:45         ` Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 21/34] mtd: rawnand: tegra: " Dmitry Osipenko
2021-08-17  8:41   ` Miquel Raynal
2021-08-17  1:27 ` [PATCH v8 22/34] spi: tegra20-slink: Add " Dmitry Osipenko
2021-08-17 12:22   ` Mark Brown
2021-08-17 15:53     ` Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 23/34] media: dt: bindings: tegra-vde: Convert to schema Dmitry Osipenko
2021-08-18  1:17   ` Rob Herring
2021-08-17  1:27 ` [PATCH v8 24/34] media: dt: bindings: tegra-vde: Document OPP and power domain Dmitry Osipenko
2021-08-18  1:17   ` Rob Herring
2021-08-17  1:27 ` [PATCH v8 25/34] media: staging: tegra-vde: Support generic power domain and OPP Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 26/34] soc/tegra: fuse: Add OPP support Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 27/34] soc/tegra: fuse: Reset hardware Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 28/34] soc/tegra: regulators: Prepare for suspend Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 29/34] soc/tegra: pmc: Enable core domain support for Tegra20 and Tegra30 Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 30/34] ARM: tegra: Add OPP tables and power domains to Tegra20 device-trees Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 31/34] ARM: tegra: Add OPP tables and power domains to Tegra30 device-trees Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 32/34] ARM: tegra: Add Memory Client resets to Tegra20 GR2D, GR3D and Host1x Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 33/34] ARM: tegra: Add Memory Client resets to Tegra30 " Dmitry Osipenko
2021-08-17  1:27 ` [PATCH v8 34/34] ARM: tegra20/30: Disable unused host1x hardware Dmitry Osipenko

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