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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Niklas Cassel <niklas.cassel@linaro.org>,
        Vinod Koul <vkoul@kernel.org>
Subject: [PATCH 5.5 263/367] arm64: dts: qcom: qcs404-evb: Set vdd_apc regulator in high power mode
Date:   Mon, 10 Feb 2020 04:32:56 -0800
Message-Id: <20200210122448.776944453@linuxfoundation.org>
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From: Niklas Cassel <niklas.cassel@linaro.org>

commit eac8ce86cb90ba96cb4bcbf2549d7a8b6938aa30 upstream.

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.

Fixes: 8faea8edbb35 ("arm64: dts: qcom: qcs404-evb: add spmi regulators")
Cc: stable@vger.kernel.org
Suggested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20191014120920.12691-1-niklas.cassel@linaro.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/arm64/boot/dts/qcom/qcs404-evb.dtsi |    1 +
 1 file changed, 1 insertion(+)

--- 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>;
 	};