From: Chanwoo Choi <cw00.choi@samsung.com>
To: Dmitry Osipenko <digetx@gmail.com>,
Thierry Reding <thierry.reding@gmail.com>,
MyungJoo Ham <myungjoo.ham@samsung.com>,
Kyungmin Park <kyungmin.park@samsung.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Michael Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@kernel.org>
Cc: linux-clk@vger.kernel.org, linux-pm@vger.kernel.org,
linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 4/5] PM / devfreq: tegra30: Use clk_round_rate_unboundly()
Date: Wed, 1 Apr 2020 08:22:45 +0900 [thread overview]
Message-ID: <147b571a-bae1-8a58-942c-579a5297299b@samsung.com> (raw)
In-Reply-To: <20200330231617.17079-5-digetx@gmail.com>
On 3/31/20 8:16 AM, Dmitry Osipenko wrote:
> The clk_round_rate() doesn't work for us properly if clock rate is bounded
> by a min/max rate that is requested by some other clk-user because we're
> building devfreq's OPP table based on the rounding.
>
> In particular this becomes a problem if display driver is probed earlier
> than devfreq, and thus, display adds a memory bandwidth request using
> interconnect API, which results in a minimum clock-rate being set for
> the memory clk. In a result, the lowest devfreq OPP rate is getting
> limited to the minimum rate imposed by the display driver.
>
> Let's use new clk_round_rate_unboundly() that resolves the problem by
> rounding clock rate without taking into account min/max limits imposed by
> active clk users.
>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
> drivers/devfreq/tegra30-devfreq.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
> index 28b2c7ca416e..34f6291e880c 100644
> --- a/drivers/devfreq/tegra30-devfreq.c
> +++ b/drivers/devfreq/tegra30-devfreq.c
> @@ -834,7 +834,7 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
>
> reset_control_deassert(tegra->reset);
>
> - rate = clk_round_rate(tegra->emc_clock, ULONG_MAX);
> + rate = clk_round_rate_unboundly(tegra->emc_clock, ULONG_MAX);
> if (rate < 0) {
> dev_err(&pdev->dev, "Failed to round clock rate: %ld\n", rate);
> return rate;
> @@ -849,7 +849,7 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
> }
>
> for (rate = 0; rate <= tegra->max_freq * KHZ; rate++) {
> - rate = clk_round_rate(tegra->emc_clock, rate);
> + rate = clk_round_rate_unboundly(tegra->emc_clock, rate);
>
> if (rate < 0) {
> dev_err(&pdev->dev,
>
Firstly, patch2 have to be reviewed for this patch.
I have no any objection. It looks good to me.
If patch1 get the confirmation from clock maintainer,
feel free to add my acked tag:
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
--
Best Regards,
Chanwoo Choi
Samsung Electronics
next prev parent reply other threads:[~2020-03-31 23:13 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-30 23:16 [PATCH v1 0/5] NVIDIA Tegra devfreq drivers improvements Dmitry Osipenko
2020-03-30 23:16 ` [PATCH v1 1/5] PM / devfreq: tegra: Add Dmitry as a maintainer Dmitry Osipenko
2020-03-31 23:13 ` Chanwoo Choi
2020-04-01 18:52 ` Dmitry Osipenko
2020-03-30 23:16 ` [PATCH v1 2/5] clk: Introduce clk_round_rate_unboundly() Dmitry Osipenko
2020-04-02 0:33 ` Michał Mirosław
2020-04-02 14:21 ` Dmitry Osipenko
2020-05-27 5:55 ` Stephen Boyd
2020-05-27 17:57 ` Dmitry Osipenko
2020-05-28 0:38 ` Stephen Boyd
2020-05-27 5:57 ` Stephen Boyd
2020-03-30 23:16 ` [PATCH v1 3/5] PM / devfreq: tegra20: Use clk_round_rate_unboundly() Dmitry Osipenko
2020-03-31 23:22 ` Chanwoo Choi
2020-03-31 23:23 ` Chanwoo Choi
2020-03-30 23:16 ` [PATCH v1 4/5] PM / devfreq: tegra30: " Dmitry Osipenko
2020-03-31 23:22 ` Chanwoo Choi [this message]
2020-03-31 23:23 ` Chanwoo Choi
2020-03-30 23:16 ` [PATCH v1 5/5] PM / devfreq: tegra30: Make CPUFreq notifier to take into account boosting Dmitry Osipenko
2020-03-31 23:29 ` Chanwoo Choi
2020-04-01 18:53 ` Dmitry Osipenko
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