diff mbox series

arm64: dts: qcom: qcs404-evb: Set vdd_apc regulator in high power mode

Message ID 20191014120920.12691-1-niklas.cassel@linaro.org (mailing list archive)
State Accepted
Commit 31f42ead57482523cbfd32264d85197c4b36c18d
Headers show
Series arm64: dts: qcom: qcs404-evb: Set vdd_apc regulator in high power mode | expand

Commit Message

Niklas Cassel Oct. 14, 2019, 12:09 p.m. UTC
vdd_apc is the regulator that supplies the main CPU cluster.

At sudden CPU load changes, we have noticed invalid page faults on
addresses with all bits shifted, as well as on addresses with individual
bits flipped.

By putting the vdd_apc regulator in high power mode, the voltage drops
during sudden load changes will be less severe, and we have not been able
to reproduce the invalid page faults with the regulator in this mode.

Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
Suggested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
 arch/arm64/boot/dts/qcom/qcs404-evb.dtsi | 1 +
 1 file changed, 1 insertion(+)

Comments

Vinod Koul Oct. 16, 2019, 8:14 a.m. UTC | #1
On 14-10-19, 14:09, Niklas Cassel wrote:
> vdd_apc is the regulator that supplies the main CPU cluster.
> 
> At sudden CPU load changes, we have noticed invalid page faults on
> addresses with all bits shifted, as well as on addresses with individual
> bits flipped.
> 
> By putting the vdd_apc regulator in high power mode, the voltage drops
> during sudden load changes will be less severe, and we have not been able
> to reproduce the invalid page faults with the regulator in this mode.

Reviewed-by: Vinod Koul <vkoul@kernel.org>

This seems a good bug fix, maybe CC stable?

> 
> Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
> Suggested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
>  arch/arm64/boot/dts/qcom/qcs404-evb.dtsi | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm64/boot/dts/qcom/qcs404-evb.dtsi b/arch/arm64/boot/dts/qcom/qcs404-evb.dtsi
> index 501a7330dbc8..522d3ef72df5 100644
> --- a/arch/arm64/boot/dts/qcom/qcs404-evb.dtsi
> +++ b/arch/arm64/boot/dts/qcom/qcs404-evb.dtsi
> @@ -73,6 +73,7 @@
>  		regulator-always-on;
>  		regulator-boot-on;
>  		regulator-name = "vdd_apc";
> +		regulator-initial-mode = <1>;
>  		regulator-min-microvolt = <1048000>;
>  		regulator-max-microvolt = <1384000>;
>  	};
> -- 
> 2.21.0
diff mbox series

Patch

diff --git a/arch/arm64/boot/dts/qcom/qcs404-evb.dtsi b/arch/arm64/boot/dts/qcom/qcs404-evb.dtsi
index 501a7330dbc8..522d3ef72df5 100644
--- a/arch/arm64/boot/dts/qcom/qcs404-evb.dtsi
+++ b/arch/arm64/boot/dts/qcom/qcs404-evb.dtsi
@@ -73,6 +73,7 @@ 
 		regulator-always-on;
 		regulator-boot-on;
 		regulator-name = "vdd_apc";
+		regulator-initial-mode = <1>;
 		regulator-min-microvolt = <1048000>;
 		regulator-max-microvolt = <1384000>;
 	};