From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?Q?Ond=c5=99ej_Jirman?= Subject: Re: [PATCH v2 14/14] ARM: dts: sun8i: Enable DVFS on Orange Pi One Date: Fri, 1 Jul 2016 03:17:35 +0200 Message-ID: <247afcd4-4b5c-3776-5392-1125b03b65b1@megous.com> References: <20160625034511.7966-1-megous@megous.com> <20160625034511.7966-15-megous@megous.com> <20160630172330.0608178e@i7> Reply-To: megous-5qf/QAjKc83QT0dZR+AlfA@public.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="MpkCpL7uXi6lOdJS8kR0oVscwbHXGRfBL" Return-path: Sender: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org In-Reply-To: <20160630172330.0608178e@i7> List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: Siarhei Siamashka , Michal Suchanek Cc: dev , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , Rob Herring , Mark Rutland , Russell King , Maxime Ripard , Chen-Yu Tsai , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , open list List-Id: devicetree@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --MpkCpL7uXi6lOdJS8kR0oVscwbHXGRfBL Content-Type: multipart/mixed; boundary="UFl34ci4G30u8hNQ8PTllb1sROwTxFqIu" From: =?UTF-8?Q?Ond=c5=99ej_Jirman?= To: Siarhei Siamashka , Michal Suchanek Cc: dev , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , Rob Herring , Mark Rutland , Russell King , Maxime Ripard , Chen-Yu Tsai , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , open list Message-ID: <247afcd4-4b5c-3776-5392-1125b03b65b1-5qf/QAjKc83QT0dZR+AlfA@public.gmane.org> Subject: Re: [linux-sunxi] [PATCH v2 14/14] ARM: dts: sun8i: Enable DVFS on Orange Pi One References: <20160625034511.7966-1-megous-5qf/QAjKc83QT0dZR+AlfA@public.gmane.org> <20160625034511.7966-15-megous-5qf/QAjKc83QT0dZR+AlfA@public.gmane.org> <20160630172330.0608178e@i7> In-Reply-To: <20160630172330.0608178e@i7> --UFl34ci4G30u8hNQ8PTllb1sROwTxFqIu Content-Type: text/plain; charset=UTF-8 On 30.6.2016 16:23, Siarhei Siamashka wrote: > On Thu, 30 Jun 2016 13:13:48 +0200 > Michal Suchanek wrote: > >> Hello, >> >> On 25 June 2016 at 05:45, wrote: >>> From: Ondrej Jirman >>> >>> Use Xulong Orange Pi One GPIO based regulator for >>> passive cooling and thermal management. >>> >>> Signed-off-by: Ondrej Jirman >>> --- >>> arch/arm/boot/dts/sun8i-h3-orangepi-one.dts | 39 +++++++++++++++++++++++++++++ >>> 1 file changed, 39 insertions(+) >>> >>> diff --git a/arch/arm/boot/dts/sun8i-h3-orangepi-one.dts b/arch/arm/boot/dts/sun8i-h3-orangepi-one.dts >>> index b1bd6b0..a38d871 100644 >>> --- a/arch/arm/boot/dts/sun8i-h3-orangepi-one.dts >>> +++ b/arch/arm/boot/dts/sun8i-h3-orangepi-one.dts >>> @@ -109,6 +109,45 @@ >>> }; >>> }; >>> >>> +&cpu0 { >>> + operating-points = < >>> + /* kHz uV */ >>> + 1296000 1300000 >>> + 1200000 1300000 >> >> First problem is that the board boots at 1008000 which is not listed >> and the kernel complains. >> >> Second problem is that the board locks up during boot with this enabled. >> >> Do you have some suggestion for alternate configuration to test? > > Maybe try the Allwinner's original DVFS table instead of these > undervolted values and see if it helps? > > https://linux-sunxi.org/index.php?title=Xunlong_Orange_Pi_PC&oldid=17753#CPU_clock_speed_limit Thanks, I'll use these. I'm not sure what will happen if regulator is not capable of providing the exact voltages specified in the operating points, though. Will it do the sane thing? :) Also LV6+ in the table is bellow specified minimum voltage in the datasheet. But then Orange Pi works at much lower voltages for me. Conversly LV1 is the absolute maximum. Recommended maximum is 1.4V So I would not use that. It might be nice to have something like that dram clock test, but for cpux freq/voltage, and collect some statistics. regards, Ondrej > While undervolting is tempting because it helps to decrease the SoC > temperature and avoid throttling, different units may have different > tolerances and one needs to be very careful when picking defaults > that are intended to work correctly on all boards. Some safety > headroom exists there for a reason. > > If I remember correctly, some people pushed for undervolting experiments > at least twice in the past (on the Banana Pi and C.H.I.P.). In both > cases this did not end up well and had to be fixed later to solve > reliability problems. > > In order to allow individual per-unit tuning, a concept of "speed > grading" may be probably introduced later. So that the board is tested > for reliability and then the speed grade rating is stored somewhere on > the non-removable storage (EEPROM, SPI flash, eFUSE, ...). Some SoC > manufacturers, such as Samsung, are already doing this with their chips. > -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. 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