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authorJon Hunter <jonathanh@nvidia.com>2015-12-08 10:26:49 +0000
committerOlof Johansson <olof@lixom.net>2015-12-22 15:41:37 -0800
commit80373d37bee562060ce4d3e5272b708e8db5d1fc (patch)
treebcd34602f98608372bf157b2575767d85a777796
parent741db4a72a06b18069667bd2683485e52a40df74 (diff)
downloadlinux-stericsson-80373d37bee562060ce4d3e5272b708e8db5d1fc.tar.gz
ARM: tegra: Fix suspend hang on Tegra124 Chromebooks
Enabling CPUFreq support for Tegra124 Chromebooks is causing the Tegra124 to hang when resuming from suspend. When CPUFreq is enabled, the CPU clock is changed from the PLLX clock to the DFLL clock during kernel boot. When resuming from suspend the CPU clock is temporarily changed back to the PLLX clock before switching back to the DFLL. If the DFLL is operating at a much lower frequency than the PLLX when we enter suspend, and so the CPU voltage rail is at a voltage too low for the CPUs to operate at the PLLX frequency, then the device will hang. Please note that the PLLX is used in the resume sequence to switch the CPU clock from the very slow 32K clock to a faster clock during early resume to speed up the resume sequence before the DFLL is resumed. Ideally, we should fix this by setting the suspend frequency so that it matches the PLLX frequency, however, that would be a bigger change. For now simply disable CPUFreq support for Tegra124 Chromebooks to avoid the hang when resuming from suspend. Fixes: 9a0baee960a7 ("ARM: tegra: Enable CPUFreq support for Tegra124 Chromebooks") Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Olof Johansson <olof@lixom.net>
-rw-r--r--arch/arm/boot/dts/tegra124-nyan.dtsi2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/boot/dts/tegra124-nyan.dtsi b/arch/arm/boot/dts/tegra124-nyan.dtsi
index 40c23a0b7cfc..ec1aa64ded68 100644
--- a/arch/arm/boot/dts/tegra124-nyan.dtsi
+++ b/arch/arm/boot/dts/tegra124-nyan.dtsi
@@ -399,7 +399,7 @@
/* CPU DFLL clock */
clock@0,70110000 {
- status = "okay";
+ status = "disabled";
vdd-cpu-supply = <&vdd_cpu>;
nvidia,i2c-fs-rate = <400000>;
};