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From:   Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Date:   Tue, 10 Dec 2019 21:04:50 +0100
Message-ID: <CAFBinCBfgxXhPKpBLdoq9AimrpaneYFgzgJoDyC-2xhbHmihpA@mail.gmail.com>
Subject: Re: [RFC-next 0/1] Odroid C2: Enable DVFS for cpu
To:     Kevin Hilman <khilman@baylibre.com>
Cc:     Anand Moon <linux.amoon@gmail.com>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Rob Herring <robh+dt@kernel.org>,
        Jerome Brunet <jbrunet@baylibre.com>,
        devicetree <devicetree@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        linux-amlogic@lists.infradead.org,
        Linux Kernel <linux-kernel@vger.kernel.org>
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On Tue, Dec 10, 2019 at 7:13 PM Kevin Hilman <khilman@baylibre.com> wrote:
>
> Anand Moon <linux.amoon@gmail.com> writes:
>
> > Hi Neil / Kevin,
> >
> > On Tue, 10 Dec 2019 at 14:13, Neil Armstrong <narmstrong@baylibre.com> wrote:
> >>
> >> On 09/12/2019 23:12, Kevin Hilman wrote:
> >> > Anand Moon <linux.amoon@gmail.com> writes:
> >> >
> >> >> Some how this patch got lost, so resend this again.
> >> >>
> >> >> [0] https://patchwork.kernel.org/patch/11136545/
> >> >>
> >> >> This patch enable DVFS on GXBB Odroid C2.
> >> >>
> >> >> DVFS has been tested by running the arm64 cpuburn
> >> >> [1] https://github.com/ssvb/cpuburn-arm/blob/master/cpuburn-a53.S
> >> >> PM-QA testing
> >> >> [2] https://git.linaro.org/power/pm-qa.git [cpufreq testcase]
> >> >>
> >> >> Tested on latest U-Boot 2019.07-1 (Aug 01 2019 - 23:58:01 +0000) Arch Linux ARM
> >> >
> >> > Have you tested with the Harkernel u-boot?
> >> >
> >> > Last I remember, enabling CPUfreq will cause system hangs with the
> >> > Hardkernel u-boot because of improperly enabled frequencies, so I'm not
> >> > terribly inclined to merge this patch.
> >
> > HK u-boot have many issue with loading the kernel, with load address
> > *it's really hard to build the kernel for HK u-boot*,
> > to get the configuration correctly.
> >
> > Well I have tested with mainline u-boot with latest ATF .
> > I would prefer mainline u-boot for all the Amlogic SBC, since
> > they sync with latest driver changes.
>
> Yes, we would all prefer mainline u-boot, but the mainline kernel needs
> to support the vendor u-boot that is shipping with the boards.  So
> until Hardkernel (and other vendors) switch to mainline u-boot we do not
> want to have upstream kernel defaults that will not boot with the vendor
> u-boot.
>
> We can always support these features, but they just cannot be enabled
> by default.
(I don't have an Odroid-C2 but I'm curious)
should Anand submit a patch to mainline u-boot instead? the
&scpi_clocks node could be enabled at runtime by mainline u-boot


Martin