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SubjectRe: [PATCH v2] ARM: dts: imx6sx-sdb: Remove OPP override
On Fri, May 05, 2017 at 02:00:17PM +0300, Leonard Crestez wrote:
> The board file for imx6sx-sdb overrides cpufreq operating points to use
> higher voltages. This is done because the board has a shared rail for
> VDD_ARM_IN and VDD_SOC_IN and when using LDO bypass the shared voltage
> needs to be a value suitable for both ARM and SOC.
>
> This only applies to LDO bypass mode, a feature not present in upstream.
> When LDOs are enabled the effect is to use higher voltages than necessary
> for no good reason.
>
> Setting these higher voltages can make some boards fail to boot with ugly
> semi-random crashes reminiscent of memory corruption. These failures only
> happen on board rev. C, rev. B is reported to still work.
>
> Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
> CC: stable@vger.kernel.org

It should have the Fixes tag below. I can add it when applying.

Fixes: 54183bd7f766 ("ARM: imx6sx-sdb: add revb board and make it default")

>
> ---
>
> It is not known exactly why setting these higher voltages causes crashes.
> Maybe this means that it's not appropriate to CC stable?

It should depend on whether we care about the crashes on stable kernel
running on Rev C board. Do we?

Shawn

>
> Removing this override is a correct change anyway because these OPP
> overrides do not serve a purpose without ldo bypass.
>
> Changes since v1:
> - Adjusted commit message
> - Link: https://lkml.org/lkml/2017/4/25/636
>
> arch/arm/boot/dts/imx6sx-sdb.dts | 17 -----------------
> 1 file changed, 17 deletions(-)
>
> diff --git a/arch/arm/boot/dts/imx6sx-sdb.dts b/arch/arm/boot/dts/imx6sx-sdb.dts
> index 5bb8fd5..d71da30 100644
> --- a/arch/arm/boot/dts/imx6sx-sdb.dts
> +++ b/arch/arm/boot/dts/imx6sx-sdb.dts
> @@ -12,23 +12,6 @@
> model = "Freescale i.MX6 SoloX SDB RevB Board";
> };
>
> -&cpu0 {
> - operating-points = <
> - /* kHz uV */
> - 996000 1250000
> - 792000 1175000
> - 396000 1175000
> - 198000 1175000
> - >;
> - fsl,soc-operating-points = <
> - /* ARM kHz SOC uV */
> - 996000 1250000
> - 792000 1175000
> - 396000 1175000
> - 198000 1175000
> - >;
> -};
> -
> &i2c1 {
> clock-frequency = <100000>;
> pinctrl-names = "default";
> --
> 2.7.4
>

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