linux-kernel - Re: Devfreq looks for unsupported frequencies on Exynos

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Date:   Fri, 4 Oct 2019 14:46:43 +0200
From:   Kamil Konieczny <k.konieczny@...sung.com>
To:     Krzysztof Kozlowski <krzk@...nel.org>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kamil Konieczny <k.konieczny@...tner.samsung.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        linux-pm@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: Devfreq looks for unsupported frequencies on Exynos

On 04.10.2019 12:31, Krzysztof Kozlowski wrote:
> 
> Hi All,
> 
> I noticed recently error logs when booting Odroid HC1 (Exynos5422) on
> exynos_defconfig, 5.4.0-rc1-next-20191004:
> [...]
> [    5.225222] exynos-bus soc:bus_wcore: dev_pm_opp_set_rate: failed to find current OPP for freq 532000000 (-34)
> [    5.225975] exynos-bus: new bus device registered: soc:bus_peri ( 67000 KHz ~  67000 KHz)
> [    5.238824] exynos-bus soc:bus_noc: dev_pm_opp_set_rate: failed to find current OPP for freq 111000000 (-34)
> [    5.245719] exynos-bus: new bus device registered: soc:bus_g2d ( 84000 KHz ~ 333000 KHz)
> [    5.252653] exynos-bus soc:bus_fsys_apb: dev_pm_opp_set_rate: failed to find current OPP for freq 222000000 (-34)
> [...]
> You can see that Exynos devfreq was trying to set 532000000 Hz for
> wcore, 111000000 for noc and 222000000 for fsys_apb. These are higher
> frequencies than we have in DTSI.
> 
> Any ideas why? It does not look normal...

Thank you for report. This is known issue, clocks left by u-boot are too
high and they are not present in opp tables. Lukasz Luba sended patchset
"[PATCH v1 00/50] Exynos5x clocks and buses changes" but it should first
be made in u-boot.

I have idea for a fix and will send it soon after weekend.

-- 
Best regards,
Kamil Konieczny
Samsung R&D Institute Poland